Add MAINTAINERS.md and RELEASING.md. (iree-org#17122)

Having these topics documented in this way is a checklist item for the
LF submission. I did my best on the MAINTAINERS.md based on some other
examples. For RELEASING.md, I attempted to document the current actual
practices.

---------

Co-authored-by: Ben Vanik <ben.vanik@gmail.com>

MAINTAINERS.md

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+# IREE Maintainer Information
+
+The IREE project operates through collaborative development via
+Discord, Pull Requests, and the mailing list. While much day to day work
+can take place without much fanfare, the variety of code in the project
+is large, and this page attempts to document "go to" people with specialist
+skills, responsibility and insights for certain components. See also
+[CODEOWNERS](.github/CODEOWNERS) for path-based reviewers for various
+components. If in doubt and there is a specific CODEOWNER for the path you
+are working on, consider that to be a more authoritative source than this file.
+This file attempts to outline long term responsibility for questions of 
+evolution, health, and design.
+
+This file is kept in the `iree` core repository but can refer to other
+affiliated repositories at need. This is meant to help "direct traffic" and
+individual projects should be authoritative about their status.
+
+## Overall
+
+Stella Laurenzo (@stellaraccident) is the maintainer of last resort for
+uncovered components, questions of project direction, etc.
+
+## Compiler Maintainers
+
+* Runtime Interface: Ben Vanik (@benvanik)
+* High Level Optimizations: Mahesh Ravishankar (@MaheshRavishankar)
+* Code Generation: Mahesh Ravishankar (@MaheshRavishankar)
+* Input Pipelines:
+
+  * Torch: Rob Suderman (@rsuderman)
+  * TOSA: Maintainer Needed
+  * StableHLO: Maintainer Needed
+
+## Runtime Maintainers
+
+* Overall: Ben Vanik (@benvanik)
+* Default HAL Drivers: Lei Zhang (@antiagainst)
+
+## Build Tools, Infra, and Dependencies
+
+* LLVM Dependency: Mahesh Ravishankar (@MaheshRavishankar)
+* CI, Docs, and Tools: Scott Todd (@ScottTodd)
+* Other Dependencies: Ben Vanik (@benvanik) and Scott Todd (@ScottTodd)
+
+## APIs
+
+* Compiler C API: Stella Laurenzo (@stellaraccident)
+* Python Bindings: Stella Laurenzo (@stellaraccident)
+* Turbine: Stella Laurenzo (@stellaraccident)
+* PJRT: Maintainer Needed
+
+## Releasing
+
+* Python Releases: Stella Laurenzo (@stellaraccident)
+* Other packages, nightlies, and infra: Maintainer Needed
+

RELEASING.md

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+# IREE Releasing
+
+This file documents the extant release process that IREE uses. This process
+and the automation (such as it is) has grown over many years and is due for
+a refresh. However, in the interests of documenting what exists, we attempt
+to do so here.
+
+## Nightly Core Releases
+
+IREE development is primarily driven via automated nightly release snapshots.
+These are scheduled automatically each day by the 
+`schedule_candidate_release.yml` workflow, which selects a green commit from
+main (for non optional CI tasks), created a tag of the format
+`candidate-{YYYYMMDD}.{BUILDNUM}` and schedules automation to populate the
+release.
+
+The `build_package.yml` workflow then runs jobs to do builds for all
+platforms and packages, finally triggering the 
+`validate_and_publish_release.yml` workflow.
+
+Release artifacts are uploaded as a GitHub
+[pre release](https://github.com/iree-org/iree/releases) and an index of files
+is updated by periodic automation at https://iree.dev/pip-release-links.html.
+
+Some debugging notes for this process are available here: 
+https://iree.dev/developers/debugging/releases/
+
+### Nightly Release Packages
+
+A number of packages are produced automatically:
+
+* `iree-dist-*.tar.xz` (manylinux x86_64 and aarch64): Install image of the
+  binaries and development assets needed to use or depend on the C/C++ parts
+  of the project.
+* `iree-compiler`: Binary Python wheels
+* `iree-runtime`: Binary Python wheels
+* `iree-tools-tf` and `iree-tools-tflite`: Pure Python wheels
+
+#### Linux Builds
+
+Binary Linux packages are built using a custom `manylinux` based Docker 
+image hosted here: https://github.com/nod-ai/base-docker-images/pkgs/container/manylinux_x86_64
+(TODO: this repository of Docker images should be moved into `iree-org`) using
+isolated self-hosted runners (only used for building checked in code) of
+sufficient size for building large components and GitHub managed runners for
+smaller components. The project aims to target all non-EOL Python versions with
+Linux builds on x86_64 and aarch64.
+
+#### Windows Builds
+
+Windows builds are built using GitHub managed large Windows runners. Due to the
+cost, the project aims to target the most recent version of Python only while
+building version N-1 for the first year of the lifecycle of the next version.
+
+Only the Python `iree-compiler` and `iree-runtime` packages are built for
+Windows.
+
+The release is published even if the MacOS build fails. When this happens, it
+is fixed forward for the next snapshot.
+
+#### MacOS Builds
+
+MacOS builds are performed using self hosted MacOS runners in a dedicated
+post-submit pool. Due to the cost, the project aims to target the most recent 
+version of Python only while building version N-1 for the first year of the 
+lifecycle of the next version.
+
+Only the Python `iree-compiler` and `iree-runtime` packages are built for
+MacOS.
+
+The release is published even if the MacOS build fails. When this happens, it
+is fixed forward for the next snapshot.
+
+## Retention
+
+The project will keep pre-release tagged releases on its releases page for a
+minimum of 6 months. Releases older than this can be purged.
+
+## Distribution to Package Registries
+
+The following package registry projects are managed as part of the IREE
+release process:
+
+### PyPI
+
+* https://pypi.org/project/iree-compiler/
+* https://pypi.org/project/iree-runtime/
+* https://pypi.org/project/iree-turbine/
+* https://pypi.org/project/shark-turbine/ (transitional until switched to
+  iree-turbine)
+* https://pypi.org/project/iree-tools-tf/
+* https://pypi.org/project/iree-tools-tflite/
+
+Deprecated projects no longer updated:
+
+* https://pypi.org/project/iree-runtime-instrumented/ (functionality is
+  included in the main iree-runtime package)
+* https://pypi.org/project/iree-tools-xla/ (functionality is no longer needed)
+
+
+## Build Promotion
+
+There are presently two build promotion processes documented:
+
+* Old one focused purely on releasing IREE core packages: 
+https://iree.dev/developers/general/release-management/
+* New one driven by the Torch frontend and documented below.
+
+The versioning scheme for 
+[iree-turbine](https://github.com/iree-org/iree-turbine) is rooted on the
+then-current PyTorch released version, with optional date-based dev/pre-release
+suffixes (i.e. `rcYYYYMMDD` or `devYYYYMMDD`) or intra PyTorch releases
+(i.e. `postVVVV`).
+
+This process is being trialed to correspond with the 2.3.0 release of PyTorch.
+In this scenario, the pinned nightly build of IREE is considered current and
+promoted as part of the Turbine release to PyPI (and the release is marked as
+not pre-release on the GitHub releases page).
+
+Promotions are done roughly monthly or at need. The schedule is shifted to
+account for extra factors as needed.
+
+In the future, we would like to adopt a real versioning scheme (beyond the
+nightly calver+build number scheme) and manage promotion and pinning of the
+core IREE dep more explicitly and in alignment with how downstreams are using
+it.
+
+### Steps to Promote
+
+There are multiple release artifacts that are deployed from this project:
+
+* shark-turbine wheel (transitional while switching to iree-turbine)
+* iree-turbine wheel
+* iree-compiler wheels
+* iree-runtime wheels
+
+Typically we deploy IREE compiler and runtime wheels along with a turbine
+release, effectively promoting a nightly.
+
+#### Building Artifacts
+
+Start with a clean clone of iree-turbine:
+
+```
+cd scratch
+git clone git@github.com:iree-org/iree-turbine.git
+cd iree-turbine
+```
+
+Build a pre-release:
+
+```
+./build_tools/build_release.py --core-version 2.3.0 --core-pre-version=rcYYYYMMDD
+```
+
+Build an official release:
+
+```
+./build_tools/build_release.py --core-version 2.3.0
+```
+
+This will download all deps, including wheels for all supported platforms and
+Python versions for iree-compiler and iree-runtime. All wheels will be placed
+in the `wheelhouse/` directory.
+
+
+#### Testing
+
+TODO: Write a script for this.
+
+```
+python -m venv wheelhouse/test.venv
+source wheelhouse/test.venv/bin/activate
+pip install -f wheelhouse iree-turbine[testing]
+# Temp: tests require torchvision.
+pip install -f wheelhouse torchvision
+pytest core/tests
+```
+
+#### Push
+
+From the testing venv, verify that everything is sane:
+
+```
+pip freeze
+```
+
+Push IREE deps (if needed/updated):
+
+```
+twine upload wheelhouse/iree_compiler-* wheelhouse/iree_runtime-*
+```
+
+Push built wheels:
+
+```
+twine upload wheelhouse/iree_turbine-* wheelhouse/shark_turbine-*
+```
+
+#### Install from PyPI and Sanity Check
+
+TODO: Script this
+
+From the testing venv:
+
+```
+pip uninstall -y shark-turbine iree-turbine iree-compiler iree-runtime
+pip install iree-turbine
+pytest core/tests
+```