Holodeck Combat Training Arena Fix and Tweaks (#21603)

This PR maps in the combat training arena AREA into the map, allowing
for it to be actually spawned.

Also changed its layout and added in in two self recharging xenofauna
guns for people to shoot the carp with.

code/modules/projectiles/projectile/beams.dm

@@ -358,6 +358,16 @@
 		SA.take_organ_damage(0, 20)
 	return TRUE
 
+/obj/projectile/beam/mousegun/xenofauna_holo
+	damage = 0
+
+/obj/projectile/beam/mousegun/xenofauna_holo/on_hit(atom/target, blocked, def_zone)
+	. = ..()
+	if(istype(target, /mob/living/simple_animal/hostile/carp/holodeck))
+		var/mob/living/simple_animal/hostile/carp/holodeck/C = target
+		C.take_organ_damage(15)
+	return TRUE
+
 /obj/projectile/beam/shotgun
 	name = "diffuse laser"
 	icon_state = "laser"