Revert "Revert "Garbage collection, asset delivery, icon2html revolution, and…" (#15816)

This reverts commit f6d0f62622.

code/modules/mob/dead/observer/logout.dm

@@ -4,4 +4,4 @@
 		if(src && !key)	//we've transferred to another mob. This ghost should be deleted.
 			qdel(src)
 		else
-			cleanup_timer = QDEL_IN(src, 10 MINUTES)
+			cleanup_timer = QDEL_IN_STOPPABLE(src, 10 MINUTES)

code/modules/mob/dead/observer/observer.dm

@@ -460,6 +460,8 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	if(target != src)
 		if(following && following == target)
 			return
+		if(following)
+			src.stop_following()
 		following = target
 		to_chat(src, "<span class='notice'>Now following [target]</span>")
 		if(ismob(target))