Replaces CEV-Eris style rocks with SS13 ones, adds Ironrock (#18898)

* replaces CEV=eris rock sprites with /tg/ ones, removes mountainrock, adds ironrock

* phew... good thing i'm purple

* Update Resources/Prototypes/Entities/Structures/Walls/asteroid.yml

Co-authored-by: Vordenburg <114301317+Vordenburg@users.noreply.github.com>

---------

Co-authored-by: Vordenburg <114301317+Vordenburg@users.noreply.github.com>

Resources/Textures/Structures/Walls/rock.rsi/meta.json

@@ -1,7 +1,7 @@
 {
     "version": 1,
     "license": "CC-BY-SA-3.0",
-    "copyright": "https://github.com/Citadel-Station-13/Citadel-Station-13-RP/blob/817e7c1f225876b45891e3f06908e6d032f0a8bc/icons/turf/walls.dmi, rock_bananium made by brainfood1183 (github) for ss14, rock_snow + rock_wall and co from https://github.com/tgstation/tgstation/tree/e929cf39cded5207d63df1fa8521f41f2816b383",
+    "copyright": "https://github.com/Citadel-Station-13/Citadel-Station-13-RP/blob/817e7c1f225876b45891e3f06908e6d032f0a8bc/icons/turf/walls.dmi, rock_bananium made by brainfood1183 (github) for ss14, rock_snow, rock_asteroid, & rock_wall and co from https://github.com/tgstation/tgstation/tree/e929cf39cded5207d63df1fa8521f41f2816b383. ironrock taken from /vg/station at commit https://github.com/vgstation-coders/vgstation13/commit/02b9f6894af4419c9f7e699a22c402b086d8067e",
     "size": {
         "x": 32,
         "y": 32
@@ -52,6 +52,36 @@
         {
             "name": "rock_wall_west"
         },
+        {
+            "name": "rock_asteroid"
+        },
+        {
+            "name": "rock_asteroid_south"
+        },
+        {
+            "name": "rock_asteroid_east"
+        },
+        {
+            "name": "rock_asteroid_north"
+        },
+        {
+            "name": "rock_asteroid_west"
+        },
+        {
+            "name": "ironrock"
+        },
+        {
+            "name": "ironrock_south"
+        },
+        {
+            "name": "ironrock_east"
+        },
+        {
+            "name": "ironrock_north"
+        },
+        {
+            "name": "ironrock_west"
+        },
         {
             "name": "rock_artifact_fragment"
         },