Adds an universal object health system. (#21266)

https://www.youtube.com/watch?v=ZpUYjpKg9KY

As per title. The goal is to add health to most objects in the game and
thus allow them to be dynamically destructible, while also avoiding
shitcode like each structure having its own snowflake health update
proc.

---------

Signed-off-by: Matt Atlas <mattiathebest2000@hotmail.it>
Co-authored-by: Matt Atlas <liermattia@gmail.com>
Co-authored-by: SleepyGemmy <99297919+SleepyGemmy@users.noreply.github.com>

code/modules/random_map/automata/diona.dm

@@ -13,14 +13,9 @@
 	density = TRUE
 	opacity = FALSE
 	layer = ABOVE_TILE_LAYER
-	var/max_health = 50
-	var/health
+	maxhealth = OBJECT_HEALTH_VERY_LOW
 	var/destroy_spawntype = /mob/living/carbon/alien/diona
 
-/obj/structure/diona/Initialize(mapload)
-	. = ..()
-	health = max_health
-
 /obj/structure/diona/attackby(obj/item/attacking_item, mob/user)
 	user.setClickCooldown(DEFAULT_ATTACK_COOLDOWN)
 	if(attacking_item.tool_behaviour == TOOL_WELDER)