Refactors is_hot and fixes some issues from the beaker lighting PR (#22964)

* Idk what I'm doing

* The is_hot refactor

* Fixes that I forgot to push before making the PR

* Update code/game/objects/items.dm

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>

* Contra review

* TODO: Find out why this isn't working

* Removes the signal stuff for now, this works

* Fixes it all

* Add new signal

* Update code/_onclick/item_attack.dm

Co-authored-by: Contrabang <91113370+Contrabang@users.noreply.github.com>

* Contra reivew

* Ayyy it works

* Merge master

* Forgot this one

* Update code/game/machinery/doors/airlock_types.dm

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>

* Update code/game/objects/structures/mineral_doors.dm

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>

* Update code/game/turfs/simulated/floor/mineral_floors.dm

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>

* Update code/game/turfs/simulated/walls_mineral.dm

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>

---------

Co-authored-by: Burzah <116982774+Burzah@users.noreply.github.com>
Co-authored-by: Contrabang <91113370+Contrabang@users.noreply.github.com>

code/modules/assembly/igniter.dm

@@ -59,3 +59,6 @@
 	if(!istype(loc, /obj/item/assembly_holder))
 		activate()
 	add_fingerprint(user)
+
+/obj/item/assembly/igniter/get_heat()
+	return 2000