RGB_
* Remove deprecated `RGB_` and Mouse keycodes * Update old mouse keycodes, 0-9/A-M * Update old mouse keycodes, N-Z & layouts * Missed some stuff
* Remove duplication of RGB Matrix defaults * Remove more duplication of defaults * fix
* Marcopad debut * Applying core review suggestions * Optional layout with backlit * Line feeds and replacing dev board configs * Function to toggle backlight * Move to RGB Matrix * Fixing capitalization * Review comments --------- Co-authored-by: Marco Pelegrini <mpelegrini@microsoft.com>