[MIRROR] Port /datum/status_effect and convert wetness and fire stacks to it (#11666)

Co-authored-by: ShadowLarkens <shadowlarkens@gmail.com>
Co-authored-by: Cameron Lennox <killer65311@gmail.com>

code/modules/admin/player_effects.dm

@@ -73,7 +73,7 @@
 			if(!istype(Tar))
 				return
 			Tar.adjust_fire_stacks(10)
-			Tar.IgniteMob()
+			Tar.ignite_mob()
 			Tar.visible_message(span_danger("[target] bursts into flames!"))
 
 		if("lightning_strike")

code/modules/admin/verbs/smite.dm

@@ -36,7 +36,7 @@
 
 		if(SMITE_SPONTANEOUSCOMBUSTION)
 			target.adjust_fire_stacks(10)
-			target.IgniteMob()
+			target.ignite_mob()
 			target.visible_message(span_danger("[target] bursts into flames!"))
 
 		if(SMITE_LIGHTNINGBOLT)