Refactored Bluetooth support to make adding new Bluetooth modules
easier in the future.
* Remove `OUT_BLE` key from QMK's keymap. `OUT_BT` is all we need now
as there's no difference anymore.
* Made BLUETOOTH_ENABLE build option legacy as not to break existing
keymaps (Falls back to existing EZ Key support if on)
* Removed `ADAFRUIT_BLE_ENABLE` build option
* Created new build option `BLUETOOTH` with module option (Currently
`AdafruitEZKey` & `AdafruitBLE`)
* Moved all LUFA bluetooth key/mouse events under `BLUETOOTH_ENABLE`
ifdef with selected modules output.
This only applies to keymaps that has combined esc/grave. Here we call it theKEY.
Think about the motion when we do shift + theKEY (typing ~), or CMD + theKEY (switching window on MAC). Based on the original code, we must do following sequence: press shift -> press theKEY -> release theKEY -> release shift. However, it is very possible and natural that we do this stroke sequence instead: press shift -> press theKEY -> release shift -> release theKEY.
If we do the 2nd stroke sequence, the code will del_key(ESC) instead of (GRV) when we release theKEY. This caused some inconvenient issues and ghost typing.
By adding a flag, this issue is eliminated and will not affect any other functions.