Spiders/carp will now pull/move water/welding fuel tanks/canisters slower and won't be able to attack stationary atmospherics equipment (#61616)

Adds 2 new elements, one for slowing down pulling of dangerous objects (dispenser tanks and canisters), and one for preventing hostile attacking of elements in a typecache.

Also updates the obj_flags bitfield 'cause I thought I was gonna use that, but I didn't.

Adds these elements to spiders and space carp (from space dragon)

code/modules/mob/living/living.dm

@@ -216,6 +216,7 @@
 	if(!client && (mob_size < MOB_SIZE_SMALL))
 		return
 	now_pushing = TRUE
+	SEND_SIGNAL(src, COMSIG_LIVING_PUSHING_MOVABLE, AM)
 	var/dir_to_target = get_dir(src, AM)
 
 	// If there's no dir_to_target then the player is on the same turf as the atom they're trying to push.

code/modules/mob/living/living_movement.dm

@@ -34,6 +34,8 @@
 
 
 /mob/living/proc/update_pull_movespeed()
+	SEND_SIGNAL(src, COMSIG_LIVING_UPDATING_PULL_MOVESPEED)
+
 	if(pulling)
 		if(isliving(pulling))
 			var/mob/living/L = pulling

code/modules/mob/living/simple_animal/hostile/giant_spider.dm

@@ -69,6 +69,8 @@
 	lay_web.Grant(src)
 	if(poison_per_bite)
 		AddElement(/datum/element/venomous, poison_type, poison_per_bite)
+	AddElement(/datum/element/nerfed_pulling, GLOB.typecache_general_bad_things_to_easily_move)
+	AddElement(/datum/element/prevent_attacking_of_types, GLOB.typecache_general_bad_hostile_attack_targets, "this tastes awful!")
 
 /mob/living/simple_animal/hostile/giant_spider/Login()
 	. = ..()

code/modules/mob/living/simple_animal/hostile/space_dragon.dm

@@ -696,7 +696,11 @@
 	if(carp_stored <= 0)
 		to_chat(user, span_warning("The rift already summoned enough carp!"))
 		return FALSE
+
 	var/mob/living/simple_animal/hostile/carp/newcarp = new /mob/living/simple_animal/hostile/carp(loc)
+	newcarp.AddElement(/datum/element/nerfed_pulling, GLOB.typecache_general_bad_things_to_easily_move)
+	newcarp.AddElement(/datum/element/prevent_attacking_of_types, GLOB.typecache_general_bad_hostile_attack_targets, "this tastes awful!")
+
 	if(!is_listed)
 		ckey_list += user.ckey
 	newcarp.key = user.key