Mortar camo variants (#6941)

# About the pull request


Adds camo variations for mortar.


![dreamseeker_hj3TU8xBmq](https://github.com/user-attachments/assets/81fc01de-abc8-4e07-9697-65c6138d099d)

Also removed some unused sprites from the file, and repurposed some.

All sprites by me.

# Explain why it's good for the game

More visuals - good.

# Testing Photographs and Procedure
<details>



![dreamseeker_v8zRYgk6UY](https://github.com/user-attachments/assets/768f9412-450d-41ee-872d-42f87a7d91c6)

<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
add: mortar camo variants
/:cl:

code/modules/cm_marines/equipment/mortar/mortars.dm

@@ -43,6 +43,17 @@
 	targ_y = deobfuscate_y(0)
 	internal_camera = new(loc)
 
+	var/new_icon_state
+	switch(SSmapping.configs[GROUND_MAP].camouflage_type)
+		if("classic")
+			icon_state = new_icon_state ? new_icon_state : "c_" + icon_state
+		if("desert")
+			icon_state = new_icon_state ? new_icon_state : "d_" + icon_state
+		if("snow")
+			icon_state = new_icon_state ? new_icon_state : "s_" + icon_state
+		if("urban")
+			icon_state = new_icon_state ? new_icon_state : "u_" + icon_state
+
 /obj/structure/mortar/Destroy()
 	QDEL_NULL(internal_camera)
 	return ..()
@@ -400,6 +411,10 @@
 	unacidable = TRUE
 	w_class = SIZE_HUGE //No dumping this in a backpack. Carry it, fatso
 
+/obj/item/mortar_kit/Initialize(...)
+	. = ..()
+	select_gamemode_skin(type)
+
 /obj/item/mortar_kit/ex_act(severity)
 	switch(severity)
 		if(EXPLOSION_THRESHOLD_MEDIUM to INFINITY)