Add support to XD60 Rev3 (#4938)

Add support to XD60 Rev3 (#4938)

* Add preliminary support to XD60 Rev3 PCB (Supports the 12 underglow LEDs, but split spacebar still not wired/implemented).

* * xd60_rev3 folder removed
* xd60 rev2 and rev3 added
* ifndef replaced with pragma once at rev3 config.h

* Readme updated

* new updated statement at keyboards/xd60/readme.md

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* Update keyboards/xd60/readme.md

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* Update keyboards/xd60/readme.md

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* Update keyboards/xd60/readme.md

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* Update keyboards/xd60/readme.md

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* * XXXXX removed and replaced with 7X
* removed unecessary declarations

* Update keyboards/xd60/keymaps/styr/keymap.c

Co-Authored-By: rodrigofeijao <hello@rodrigofeijao.com>
* action_layer.h include removed

* * action_get_macro removed
* IS_COMMAND() removed
* BOOTLOADER defined