Combat/Stun (slip) overhaul staging, mobility flags, adds crawling (#39967)

Aiming to implement the framework oranges has detailed in https://tgstation13.org/phpBB/viewtopic.php?f=10&t=19102
Moves canmove to a bitflag in a new variable called mobility_flags, that will allow finer grain control of what someone can do codewise, for example, letting them move but not stand up, or stand up but not move.

Adds Immobilize()d status effect that freezes movement but does not prevent anything else.
Adds Paralyze()d which is oldstun "You can't do anything at all and knock down).
Stun() will now prevent any item/UI usage and movement (which is similar to before).
Knockdown() will now only knockdown without preventing item usage/movement.
People knocked down will be able to crawl at softcrit-speeds
Refactors some /mob variables and procs to /mob/living.
update_canmove() refactored to update_mobility() and will handle mobility_flags instead of the removed canmove

cl
rscadd: Crawling is now possible if you are down but not stunned. Obviously, you will be slower.
/cl
Refactors are done. I'd rather get this merged faster than try to fine tune stuff like slips. The most obvious gameplay effect this pr has will be crawling, and I believe I made tiny tweaks but I can't find it Anything I missed or weird behavior should be reported.

code/game/objects/items/robot/robot_items.dm

@@ -22,7 +22,7 @@
 			return
 
 	user.do_attack_animation(M)
-	M.Knockdown(100)
+	M.Paralyze(100)
 	M.apply_effect(EFFECT_STUTTER, 5)
 
 	M.visible_message("<span class='danger'>[user] has prodded [M] with [src]!</span>", \
@@ -76,15 +76,14 @@
 					user.do_attack_animation(M, ATTACK_EFFECT_BOOP)
 					playsound(loc, 'sound/weapons/tap.ogg', 50, 1, -1)
 				else if(ishuman(M))
-					if(M.lying)
+					if(!(user.mobility_flags & MOBILITY_STAND))
 						user.visible_message("<span class='notice'>[user] shakes [M] trying to get [M.p_them()] up!</span>", \
 										"<span class='notice'>You shake [M] trying to get [M.p_them()] up!</span>")
 					else
 						user.visible_message("<span class='notice'>[user] hugs [M] to make [M.p_them()] feel better!</span>", \
 								"<span class='notice'>You hug [M] to make [M.p_them()] feel better!</span>")
 					if(M.resting)
-						M.resting = FALSE
-						M.update_canmove()
+						M.set_resting(FALSE, TRUE)
 				else
 					user.visible_message("<span class='notice'>[user] pets [M]!</span>", \
 							"<span class='notice'>You pet [M]!</span>")
@@ -92,7 +91,7 @@
 		if(1)
 			if(M.health >= 0)
 				if(ishuman(M))
-					if(M.lying)
+					if(!(M.mobility_flags & MOBILITY_STAND))
 						user.visible_message("<span class='notice'>[user] shakes [M] trying to get [M.p_them()] up!</span>", \
 										"<span class='notice'>You shake [M] trying to get [M.p_them()] up!</span>")
 					else if(user.zone_selected == BODY_ZONE_HEAD)
@@ -103,8 +102,7 @@
 						user.visible_message("<span class='warning'>[user] hugs [M] in a firm bear-hug! [M] looks uncomfortable...</span>", \
 								"<span class='warning'>You hug [M] firmly to make [M.p_them()] feel better! [M] looks uncomfortable...</span>")
 					if(M.resting)
-						M.resting = FALSE
-						M.update_canmove()
+						M.set_resting(FALSE, TRUE)
 				else
 					user.visible_message("<span class='warning'>[user] bops [M] on the head!</span>", \
 							"<span class='warning'>You bop [M] on the head!</span>")
@@ -116,7 +114,7 @@
 						M.electrocute_act(5, "[user]", safety = 1)
 						user.visible_message("<span class='userdanger'>[user] electrocutes [M] with [user.p_their()] touch!</span>", \
 							"<span class='danger'>You electrocute [M] with your touch!</span>")
-						M.update_canmove()
+						M.update_mobility()
 					else
 						if(!iscyborg(M))
 							M.adjustFireLoss(10)
@@ -330,7 +328,7 @@
 					C.stuttering += 10
 					C.Jitter(10)
 				if(2)
-					C.Knockdown(40)
+					C.Paralyze(40)
 					C.confused += 10
 					C.stuttering += 15
 					C.Jitter(25)

code/game/objects/items/robot/robot_parts.dm

@@ -317,8 +317,8 @@
 			O.robot_suit = src
 
 			if(!locomotion)
-				O.lockcharge = 1
-				O.update_canmove()
+				O.lockcharge = TRUE
+				O.update_mobility()
 				to_chat(O, "<span class='warning'>Error: Servo motors unresponsive.</span>")
 
 		else
@@ -357,7 +357,7 @@
 			O.robot_suit = src
 			if(!locomotion)
 				O.lockcharge = TRUE
-				O.update_canmove()
+				O.update_mobility()
 
 	else if(istype(W, /obj/item/pen))
 		to_chat(user, "<span class='warning'>You need to use a multitool to name [src]!</span>")