Add Mod Mmm PCB

[dcpedit]

Description

This adds support for the Mod Mmm PCB which is a replacement PCB for the IBM Model M. It comes in two variants: standard staggered layout, and ortholinear layout. Project is open source and can be found on GitHub: https://github.com/dcpedit/mod-mmm

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[dcpedit]

The firmware no longer compiles when I remove rules.mk. I get the following error:

make dcpedit/modmmm/standard:via      
QMK Firmware 0.23.9
make: *** No rule to make target 'dcpedit/modmmm/standard:via'. Stop.

I also get the following error when I rename info.json to keyboard.json:

make dcpedit/modmmm/standard:via
QMK Firmware 0.23.9
☒ dcpedit/modmmm/standard: No LAYOUTs defined! Need at least one layout defined in info.json.
Making dcpedit/modmmm/standard with keymap via

[dunk2k]

QMK Repo version, on your local repository, is out of date - please update.

Regarding rules.mk and info.json > keyboard.json, build markers have changed as of #23293
This changes means:

1. rules.mk is no longer used to denote which directory level firmware is built from
2. keyboard.json is used to denote which directory to build firmware from, info.json is used to populate keyboard information directory level(s) above keyboard.json

[dunk2k]

@dcpedit
Please can PR Checklist guidance be followed regarding PCBs with multiple physical layouts

[dcpedit]

@dunk2k I think I finally understand now. Thanks for walking me through this

[github-actions]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with bug, awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[dcpedit]

Waiting for review

[github-actions]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with bug, awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[fauxpark]

Via keymaps need to be removed.

[dcpedit]

Via keymaps need to be removed.

@fauxpark I'm not sure I understand. Isn't keymap.json needed when I compile for VIA?

UPDATE: Nevermind, I found the PR that addresses the change. I've removed the VIA keymaps.