Gibs you leave are now based on your biotype/chest bodypart, improves gibber VFX (#91421)

## About The Pull Request

* When gibbing mobs, spawned gib type is now based on mob's biotypes if
they're not a carbon, or their chest (or first) bodypart if they are,
rather than requiring a proc override for every single mob. This means
that a few robotic mobs no longer drop meaty gibs, and that gibbing
androids now produces cyborg gibs instead of a meaty surprise, plus they
should no longer runtime when trying to gib a robot. Gibs also are now
spawned around the gibber and streak outwards instead of magically
teleporting a few tiles away, for some visual flair.
* Fixed meat not overriding blood DNA on blood_walk component which made
xeno and lizard meat leave behind orange trails instead of proper
lime/dark green blood colors (due to them keeping human meat DNA).
* Brightened up the gibber blood overlay I've missed, so it should be
consistent with old blood colors now.
* Also cleaned up the gibspawner code.

## Why It's Good For The Game

Biotype/chest changes should make devs lives easier and gameplay a bit
more consistent, and streaking just makes the process look slightly
better.

## Changelog
🆑
add: Androids and fully augmented humans now drop robotic gibs instead
of meat
add: Improved gibber VFX
fix: Fixed gibber overlays being darker than intended
fix: Fixed xenomorph and lizard meat leaving orange trails behind
code: Improved gibs and gibspawner code
/🆑

code/modules/mob/living/basic/alien/_alien.dm

@@ -85,11 +85,10 @@
 	visible_message(span_alertalien("[src] lays an egg!"))
 	new /obj/structure/alien/egg(loc)
 
-/mob/living/basic/alien/spawn_gibs(drop_bitflags=NONE)
-	if(drop_bitflags & DROP_BODYPARTS)
-		new /obj/effect/gibspawner/xeno(drop_location(), src)
-	else
-		new /obj/effect/gibspawner/xeno/bodypartless(drop_location(), src)
-
 /mob/living/basic/alien/get_bloodtype()
 	return get_blood_type(BLOOD_TYPE_XENO)
+
+/mob/living/basic/alien/get_gibs_type(drop_bitflags = NONE)
+	if(drop_bitflags & DROP_BODYPARTS)
+		return /obj/effect/gibspawner/xeno
+	return /obj/effect/gibspawner/xeno/bodypartless