add simple gmmk pro macos keymap with rgb

[alexmarmon]

Description

• Working basic RGB thanks to AW20216 use register increment for framebuffer flushes #13430
• Restore working rotary knob volume control
• Add media_previous and media_next to FN+left and FN+right

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).