[MIRROR] Color standardization, vars moved, and signals (#194)

* Color standardization, vars moved, and signals (#52574)

    Defined all the existing light_color values.
    Moved their definitions to colors.dm
    Made white the default color. It was so already, but that was very obscured.
    Moved the atom light-related variables to the atom definition.
    Wrapped changes to variables such as light_color into procs that report the event through signals.
    Moved the light_on variable to the atom level, also adding a signal for its changing, to represent toggling lights.
    Cleaned up a little bit of code in where new variables were defined before redefinitions.

This is all atomization to reduce changes in #52413
None of this affect gameplay at all, it's all code cleaning and refactoring.

There's more colors to standardize, a search for color = will find lots of targets, and I see little need to have both the LIGHT_COLOR and COLOR patterns, but I don't want to make this PR bigger than it already is.

* Color standardization, vars moved, and signals

Co-authored-by: Rohesie <rohesie@gmail.com>

code/modules/shuttle/syndicate.dm

@@ -6,7 +6,7 @@
 	circuit = /obj/item/circuitboard/computer/syndicate_shuttle
 	icon_screen = "syndishuttle"
 	icon_keyboard = "syndie_key"
-	light_color = LIGHT_COLOR_RED
+	light_color = COLOR_SOFT_RED
 	req_access = list(ACCESS_SYNDICATE)
 	shuttleId = "syndicate"
 	possible_destinations = "syndicate_away;syndicate_z5;syndicate_ne;syndicate_nw;syndicate_n;syndicate_se;syndicate_sw;syndicate_s;syndicate_custom"