Gun refactor (#8301)

Co-authored-by: Kara <lunarautomaton6@gmail.com>
Co-authored-by: T-Stalker <le0nel_1van@hotmail.com>
Co-authored-by: T-Stalker <43253663+DogZeroX@users.noreply.github.com>
Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>
Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Resources/Textures/Objects/Weapons/Guns/Ammunition/Magazine/Shotgun/m12.rsi/meta.json

@@ -8,10 +8,16 @@
     "copyright": "https://github.com/discordia-space/CEV-Eris/raw/831c7c2743530e8a31910d781bae9dc34f3f1ec8/icons/obj/ammo_mags.dmi",
     "states": [
         {
-            "name": "icon"
+            "name": "base"
         },
         {
-            "name": "base"
+            "name": "beanbag"
+        },
+        {
+            "name": "pellets"
+        },
+        {
+            "name": "slug"
         },
         {
             "name": "mag-1"

Resources/Textures/Objects/Weapons/Guns/Ammunition/Magazine/Shotgun/m12_beanbag.rsi/meta.json

@@ -1,20 +0,0 @@
-{
-    "version": 1,
-    "size": {
-        "x": 32,
-        "y": 32
-    },
-    "license": "CC-BY-SA-3.0",
-    "copyright": "https://github.com/discordia-space/CEV-Eris/raw/831c7c2743530e8a31910d781bae9dc34f3f1ec8/icons/obj/ammo_mags.dmi",
-    "states": [
-        {
-            "name": "icon"
-        },
-        {
-            "name": "base"
-        },
-        {
-            "name": "mag-1"
-        }
-    ]
-}

Resources/Textures/Objects/Weapons/Guns/Ammunition/Magazine/Shotgun/m12_pellets.rsi/meta.json

@@ -1,20 +0,0 @@
-{
-    "version": 1,
-    "size": {
-        "x": 32,
-        "y": 32
-    },
-    "license": "CC-BY-SA-3.0",
-    "copyright": "https://github.com/discordia-space/CEV-Eris/raw/831c7c2743530e8a31910d781bae9dc34f3f1ec8/icons/obj/ammo_mags.dmi",
-    "states": [
-        {
-            "name": "icon"
-        },
-        {
-            "name": "base"
-        },
-        {
-            "name": "mag-1"
-        }
-    ]
-}

Resources/Textures/Objects/Weapons/Guns/Ammunition/Magazine/Shotgun/m12_slug.rsi/meta.json

@@ -1,20 +0,0 @@
-{
-    "version": 1,
-    "size": {
-        "x": 32,
-        "y": 32
-    },
-    "license": "CC-BY-SA-3.0",
-    "copyright": "https://github.com/discordia-space/CEV-Eris/raw/831c7c2743530e8a31910d781bae9dc34f3f1ec8/icons/obj/ammo_mags.dmi",
-    "states": [
-        {
-            "name": "icon"
-        },
-        {
-            "name": "base"
-        },
-        {
-            "name": "mag-1"
-        }
-    ]
-}