demos config (#50615)

* demos config

* safety

* functional

* cut lists on init

code/controllers/configuration/entries/general.dm

@@ -96,6 +96,9 @@
 
 /datum/config_entry/flag/log_shuttle // log shuttle related actions, ie shuttle computers, shuttle manipulator, emergency console
 
+/// Whether demos are written, if not set demo SS never initializes
+/datum/config_entry/flag/demos_enabled
+
 /datum/config_entry/flag/allow_admin_ooccolor	// Allows admins with relevant permissions to have their own ooc colour
 
 /datum/config_entry/flag/allow_admin_asaycolor //Allows admins with relevant permissions to have a personalized asay color

code/controllers/subsystem/demo.dm

@@ -61,6 +61,14 @@ SUBSYSTEM_DEF(demo)
 	last_chat_message = text
 
 /datum/controller/subsystem/demo/Initialize()
+	if(!CONFIG_GET(flag/demos_enabled))
+		flags |= SS_NO_FIRE
+		can_fire = FALSE
+		marked_dirty.Cut()
+		marked_new.Cut()
+		marked_turfs.Cut()
+		return ..()
+
 	WRITE_LOG_NO_FORMAT(GLOB.demo_log, "demo version 1\n") // increment this if you change the format
 	if(GLOB.revdata)
 		WRITE_LOG_NO_FORMAT(GLOB.demo_log, "commit [GLOB.revdata.originmastercommit || GLOB.revdata.commit]\n")
@@ -394,11 +402,15 @@ SUBSYSTEM_DEF(demo)
 	..(msg)
 
 /datum/controller/subsystem/demo/proc/mark_turf(turf/T)
+	if(!can_fire)
+		return
 	if(!isturf(T))
 		return
 	marked_turfs[T] = TRUE
 
 /datum/controller/subsystem/demo/proc/mark_new(atom/movable/M)
+	if(!can_fire)
+		return
 	if(!isobj(M) && !ismob(M))
 		return
 	if(M.gc_destroyed)
@@ -409,6 +421,8 @@ SUBSYSTEM_DEF(demo)
 
 // I can't wait for when TG ports this and they make this a #define macro.
 /datum/controller/subsystem/demo/proc/mark_dirty(atom/movable/M)
+	if(!can_fire)
+		return
 	if(!isobj(M) && !ismob(M))
 		return
 	if(M.gc_destroyed)
@@ -417,6 +431,8 @@ SUBSYSTEM_DEF(demo)
 		marked_dirty[M] = TRUE
 
 /datum/controller/subsystem/demo/proc/mark_destroyed(atom/movable/M)
+	if(!can_fire)
+		return
 	if(!isobj(M) && !ismob(M))
 		return
 	if(marked_new[M])