Mob Destroy Refactoring (#22573)

Refactoring the entire destroy proc path from Mob Human all the way down
to Atom while trying to find the causes for the damn mob human hard
deletes. This PR comprehensively reorganizes every single stray
snowflake var used by /atom/ all the way to /mob/living/carbon/human,
and makes sure that every var that COULD store a reference, is now
cleared during the entirety of the Mob Destroy() parent hierarchy.

This may very well be the end of the lag war. 

In total, I've hunted down and cleared 39 hanging references between
/atom and /mob/living/carbon/human

---------

Signed-off-by: VMSolidus <evilexecutive@gmail.com>

code/game/objects/effects/effect_system.dm

@@ -14,10 +14,6 @@ would spawn and follow the beaker, even if it is carried or thrown.
 	pass_flags = PASSTABLE | PASSGRILLE
 	blocks_emissive = EMISSIVE_BLOCK_GENERIC
 
-/obj/effect/Destroy()
-	QDEL_NULL(reagents)
-	return ..()
-
 /datum/effect/effect/system
 	var/number = 3
 	var/cardinals = 0

code/game/objects/objs.dm

@@ -108,6 +108,15 @@
 	var/persistant_objects_expiration_time_days = PERSISTENT_DEFAULT_EXPIRATION_DAYS
 	/* END PERSISTENCE VARS */
 
+	/// for easy reference of talking atoms
+	var/datum/talking_atom/talking_atom
+
+	/// Whether this object has been contaminated by atmos gasses like chlorine or phoron.
+	var/contaminated = FALSE
+
+	/// Allow overriding rad resistance.
+	var/rad_resistance_modifier = 1
+
 /obj/Initialize(mapload, ...)
 	. = ..()
 	if(maxhealth)