Camera net/chunk refactor. Slight performance improvements and makes it GC properly (#20302)

* Add SScamera

* Refactor camera

* Refactor how camera chunks add/remove cams

* Use CAMERA_VIEW_DISTANCE to determine max view dist of cam

* Fix movable cameras and optimise them

* Optimise update()

* Ensure aiEyes get removed properly when deleted

* Final optimisations and refactoring

* Fix cameras being EMPed

* Shits fixed

* AA review

* Fix merge mistake

* Add comment about early return

* Seans review

* the it the

Co-authored-by: S34N <12197162+S34NW@users.noreply.github.com>

* Update code/game/machinery/camera/camera.dm

Co-authored-by: Ryan <80364400+Sirryan2002@users.noreply.github.com>

* Ensure the robit has a camera before updating it

---------

Co-authored-by: S34N <12197162+S34NW@users.noreply.github.com>
Co-authored-by: Charlie <69320440+hal9000PR@users.noreply.github.com>
Co-authored-by: Ryan <80364400+Sirryan2002@users.noreply.github.com>

code/controllers/subsystem/camera.dm

@@ -0,0 +1,24 @@
+// Subsystem that controls the camera vision tiles
+SUBSYSTEM_DEF(camera)
+	name = "Camera"
+	flags = SS_BACKGROUND | SS_NO_INIT
+	priority = FIRE_PRIORITY_CAMERA
+	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
+	wait = 2.5 SECONDS
+	offline_implications = "AI camera view won't update. No immediate action is needed."
+	var/list/chunk_queue = list()
+
+/datum/controller/subsystem/camera/fire(resumed)
+	for(var/datum/camerachunk/chunk as anything in chunk_queue)
+		chunk.update()
+		chunk_queue -= chunk
+		if(MC_TICK_CHECK)
+			return
+
+
+/datum/controller/subsystem/camera/proc/queue(datum/camerachunk/chunk)
+	if(!chunk_queue[chunk])
+		chunk_queue[chunk] = chunk
+
+/datum/controller/subsystem/camera/proc/remove_from_queue(datum/camerachunk/chunk)
+	chunk_queue -= chunk