[Keymap] Update personal userspace and keymaps (now with 4 spaces!) (#5774)

* Add FnLk to Melody96 bottom row

* Update conditional in userspace makefile

Thanks @drashna

* Add F keys to Melody96 Fn layer

* Add FN_ESC alias to userspace

* Update KBD6X keymap

* Fix RGB_MATRIX_ENABLE constant name in #if

* Remove trailing \ from LAYOUT macro calls

* Set RGB mode on EEPROM reset in KBD6X

* Swap right and middle mouse buttons in KBD6X

* Rearrange RGB controls in KBD6X

* Update keycode aliases, replace CLEAR with DEL_NXT in KBD6X

Add Clear to KBD6X as RCtrl+`

* Convert code to 4 space indents

* Tweak RCTRL layer functionality

* Replace NUMPAD custom keycode with layer state logic

* Update RGB_MATRIX_ENABLE check

Co-Authored-By: vomindoraan <vomindoraan@gmail.com>