Backlight abstraction and other changes (#439)
* redoes matrix pins, abstracts backlight code for B5,6,7
* slimming down keyboard stuff, backlight breathing implemented
* don't call backlight init when no pin
* cleans up user/kb/quantum calls, keyboard files
* fix pvc atomic
* replaces CHANNEL with correct var in breathing
* removes .hexs, updates readmes, updates template
* cleans-up clueboards, readmes to lowercase
* updates readme