Redoes how alarms are handled, moves their behavior to datums (#60060)

* Adds in a set of datums to support sending, listening and storing alerts
In contrast to the old system, we now store a list of send alerts on the listener, rather then the area itself.

This makes clearing "our" alerts on destroy not a massive headache.

In addition, we now use a direct ref to the area's cameras list and signals to prevent camera hard deletes. This, combined with the aformentioned ability to clear, virtually eliminates hard deletes
sourced from alerts caused by strange senarios like the alert source moving its tile.

* Converts areas to the system, of note is the fact that areas no longer store a bool that determins if an alert
for power or atmos has been sent, that's instead handled by the alert sender datum. This means the sources list
on alert listeners actually means something

additionally, in order to prevent dumbassery with fire alarms since they're area based, fire alerts are sent by
an alert handler on the area itself

code/game/objects/structures/displaycase.dm

@@ -20,6 +20,8 @@
 	var/list/start_showpieces = list() //Takes sublists in the form of list("type" = /obj/item/bikehorn, "trophy_message" = "henk")
 	var/trophy_message = ""
 	var/glass_fix = TRUE
+	///Represents a signel source of screaming when broken
+	var/datum/alarm_handler/alarm_manager
 
 /obj/structure/displaycase/Initialize()
 	. = ..()
@@ -32,6 +34,7 @@
 	if(start_showpiece_type)
 		showpiece = new start_showpiece_type (src)
 	update_appearance()
+	alarm_manager = new(src)
 
 /obj/structure/displaycase/vv_edit_var(vname, vval)
 	. = ..()
@@ -49,6 +52,7 @@
 /obj/structure/displaycase/Destroy()
 	QDEL_NULL(electronics)
 	QDEL_NULL(showpiece)
+	QDEL_NULL(alarm_manager)
 	return ..()
 
 /obj/structure/displaycase/examine(mob/user)
@@ -98,6 +102,10 @@
 		return
 	var/area/alarmed = get_area(src)
 	alarmed.burglaralert(src)
+
+	alarm_manager.send_alarm(ALARM_BURGLAR)
+	addtimer(CALLBACK(alarm_manager, /datum/alarm_handler/proc/clear_alarm, ALARM_BURGLAR), 1 MINUTES)
+
 	playsound(src, 'sound/effects/alert.ogg', 50, TRUE)
 
 /obj/structure/displaycase/update_overlays()
@@ -122,7 +130,7 @@
 			to_chat(user,  span_notice("You [open ? "close":"open"] [src]."))
 			toggle_lock(user)
 		else
-			to_chat(user,  span_alert("Access denied."))
+			to_chat(user, span_alert("Access denied."))
 	else if(W.tool_behaviour == TOOL_WELDER && !user.combat_mode && !broken)
 		if(obj_integrity < max_integrity)
 			if(!W.tool_start_check(user, amount=5))