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

keyboards/clueboard2/keymaps/max/keymap.c

@@ -1,9 +1,5 @@
 #include "clueboard2.h"
 
-#ifdef ENABLE_RGBLIGHT
-#include "rgblight.h"
-#endif
-
 // Used for SHIFT_ESC
 #define MODS_CTRL_MASK  (MOD_BIT(KC_LSHIFT)|MOD_BIT(KC_RSHIFT))