github: add issue and pull request templates

Fix: nodejs#5246
PR-URL: nodejs#5291
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Steven R. Loomis <srloomis@us.ibm.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,14 @@
+_Thanks for wanting to report an issue you've found in Node.js. Please delete
+this text and fill in the template below. If unsure about something, just do as
+best as you're able._
+
+_Note that it will be much easier for us to fix the issue if a test case that
+reproduces the problem is provided. Ideally this test case should not have any
+external dependencies. We understand that it is not always possible to reduce
+your code to a small test case, but we would appreciate to have as much data as
+possible. Thank you!_
+
+* **Version**: _output of `node -v`_
+* **Platform**: _either `uname -a` output, or if Windows, version and 32-bit or
+  64-bit_
+* **Subsystem**: _optional. if known - please specify affected core module name_

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,24 @@
+### Description of change
+
+_Please provide a description of the change here._
+
+### Pull Request check-list
+
+_Please make sure to review and check all of these items:_
+
+- [ ] Does `make -j8 test` (UNIX) or `vcbuild test nosign` (Windows) pass with
+  this change (including linting)?
+- [ ] Is the commit message formatted according to [CONTRIBUTING.md][0]?
+- [ ] If this change fixes a bug (or a performance problem), is a regression
+  test (or a benchmark) included?
+- [ ] Is a documentation update included (if this change modifies
+  existing APIs, or introduces new ones)?
+
+_NOTE: these things are not required to open a PR and can be done afterwards /
+while the PR is open._
+
+### Affected core subsystem(s)
+
+_Please provide affected core subsystem(s) (like buffer, cluster, crypto, etc)_
+
+[0]: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md#step-3-commit