SPECIES NUKING 2023: Moves speed modifier to bodyparts (#76336)

## About The Pull Request

As we all know, speed is stored in the legs.

## Why It's Good For The Game

Potential for more medical abominations.
Potential for adding augmented legs that make you speedier (?)

## Changelog

🆑
refactor: Species speed is now stored in bodyparts. Leg transplants from
slower species will make you slower.
/🆑

---------

Co-authored-by: san7890 <the@san7890.com>
Co-authored-by: ATH1909 <42606352+ATH1909@users.noreply.github.com>

code/modules/surgery/bodyparts/_bodyparts.dm

@@ -62,6 +62,8 @@
 	var/list/embedded_objects = list()
 	/// are we a hand? if so, which one!
 	var/held_index = 0
+	/// A speed modifier we apply to the owner when attached, if any. Positive numbers make it move slower, negative numbers make it move faster.
+	var/speed_modifier = 0
 
 	// Limb disabling variables
 	///Controls if the limb is disabled. TRUE means it is disabled (similar to being removed, but still present for the sake of targeted interactions).

code/modules/surgery/bodyparts/dismemberment.dm

@@ -95,6 +95,8 @@
 	//limb is out and about, it can't really be considered an implant
 	bodypart_flags &= ~BODYPART_IMPLANTED
 	owner.remove_bodypart(src)
+	if(speed_modifier)
+		owner.update_bodypart_speed_modifier()
 
 	for(var/datum/wound/wound as anything in wounds)
 		wound.remove_wound(TRUE)
@@ -336,6 +338,8 @@
 			if(hand)
 				hand.update_appearance()
 		new_limb_owner.update_worn_gloves()
+	if(speed_modifier)
+		new_limb_owner.update_bodypart_speed_modifier()
 
 	if(special) //non conventional limb attachment
 		for(var/datum/surgery/attach_surgery as anything in new_limb_owner.surgeries) //if we had an ongoing surgery to attach a new limb, we stop it.

code/modules/surgery/bodyparts/species_parts/misc_bodyparts.dm

@@ -28,11 +28,13 @@
 	limb_id = SPECIES_SNAIL
 	unarmed_damage_high = 0.5
 	burn_modifier = 2
+	speed_modifier = 3 //disgustingly slow
 
 /obj/item/bodypart/leg/right/snail
 	limb_id = SPECIES_SNAIL
 	unarmed_damage_high = 0.5
 	burn_modifier = 2
+	speed_modifier = 3 //disgustingly slow
 
 ///ABDUCTOR
 /obj/item/bodypart/head/abductor
@@ -194,6 +196,16 @@
 	limb_id = SPECIES_ZOMBIE
 	should_draw_greyscale = FALSE
 
+/obj/item/bodypart/leg/left/zombie/infectious
+	limb_id = SPECIES_ZOMBIE
+	should_draw_greyscale = FALSE
+	speed_modifier = 0.8 //braaaaains
+
+/obj/item/bodypart/leg/right/zombie/infectious
+	limb_id = SPECIES_ZOMBIE
+	should_draw_greyscale = FALSE
+	speed_modifier = 0.8 //braaaaains
+
 ///PODPEOPLE
 /obj/item/bodypart/head/pod
 	limb_id = SPECIES_PODPERSON
@@ -377,6 +389,7 @@
 	unarmed_damage_high = 21
 	unarmed_stun_threshold = 14
 	burn_modifier = 1.25
+	speed_modifier = 0.75 //big big fungus
 
 /obj/item/bodypart/leg/right/mushroom
 	limb_id = SPECIES_MUSHROOM
@@ -384,6 +397,7 @@
 	unarmed_damage_high = 21
 	unarmed_stun_threshold = 14
 	burn_modifier = 1.25
+	speed_modifier = 0.75 //big fungus big fungus
 
 //GOLEM
 /obj/item/bodypart/head/golem