Added support for backlight on diverge3 , and added a UK iso layout (#4392)

Added support for backlight on diverge3 , and added a UK iso layout (#4392)

* Added support for backlight , and a UK iso layout

Added support for backlight , and a UK iso layout. Now uses the SPLIT_KEYBOARD #define rather than relying on lets split

* Update keyboards/diverge3/keymaps/isoUK/keymap.c

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/isoUK/keymap.c

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Simplified the lower layer

Simplified the lower layer

* dir rename to snake case

dir rename to snake case

* changed dir case

changed dir case

* Update keyboards/diverge3/rules.mk

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/keymap.c

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/keymap.c

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/keymap.c

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* Update keyboards/diverge3/keymaps/iso_uk/config.h

Co-Authored-By: mcmadhatter <mcmadhatter@hotmail.com>
* aligned and tidyied up

aligned and tidyied up