[User] Update personal userspace and keymaps, add reactive underglow (#6410)

[User] Update personal userspace and keymaps, add reactive underglow (#6410)

* Update MODERN_DOLCH_RED color

* Remove unused RAL_LAL tap dance

* Disable Space Cadet on all boards

* Rework SEND_STRING_CLEAN into CLEAN_MODS, fix DST_P_R/DST_N_A

* Disable unnecessary underglow animations

* Rearrange feature flags in rules.mk files

* Change custom colors from structs to defines

* Add some explicit initializers

* Add MODERN_DOLCH_CYAN color

* Add IS_LAYER_ON_STATE()/IS_LAYER_OFF_STATE() macros

* Add led_set_keymap() template function

* Change underglow color based on Caps/Fn state

* Preserve val when changing underglow colors

* Only trigger Fn light for Fn layer

* Refactor fn_light() and caps_light() slightly

* Add comments to fn_light() and caps_light()