Keymap: Redox: add a new Colemak keymap, macOS oriented. (#3861)

Keymap: Redox: add a new Colemak keymap, macOS oriented. (#3861)

* Add my own keymap to the list of available Redox keymaps.

This keymap is a Colemak keymap, and is meant to be used on Mac OS.
More information can be found in the readme.

* Fix "macOS" typo and remove mention of the license.

This directory inherits the project's license.

* Add missing custom keycode.

* Address feedback from PR review

- Remove deprecated code
- Remove RGB logic since it is overwritten by code running later.