Start Bluetooth API

[fauxpark]

Description

This is pretty barebones for the moment, and I'm not entirely sure whether this implementation or a more RGB Matrix-esque driver model is better. At the very least it abstracts away the existing driver-specific function calls in keyboard.c and host.c.

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).

[zvecr]

At the very least it abstracts away the existing driver-specific function calls in keyboard.c and host.c

Thats a decent enough iteration in my book. Having all the existing fragmentation removed from host/keyboard helps with some of the refactoring ive got staged.