Add keychron k15 pro

[KeychronMacro]

As the title and request for a review, thanks!

Description

• Added k10_pro/jis/rgb and k10_pro/jis/white
• Added k15_pro, including rgb and white versions
• Added keychron/common, put the matrix.c and common.mk into it

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).