Adds the Improvised Shotgun (#18025)

* improvised shotguns

* spaghetti

* progress so far (TODO: rename modular_reciever.yml)

* i forgotted

* everything so far

* fuck fuck fuck (boner boner)

* ganon: You must die

* bobie

* boob boob booby balls

Resources/Textures/Objects/Weapons/Guns/Ammunition/Casings/shotgun_shell.rsi/meta.json

@@ -5,7 +5,7 @@
         "y": 32
     },
     "license": "CC-BY-SA-3.0",
-    "copyright": "https://github.com/discordia-space/CEV-Eris/raw/e1d495c3faf4642b6ec1c4be8acc7cd5bc51d785/icons/obj/ammo.dmi",
+    "copyright": "https://github.com/discordia-space/CEV-Eris/raw/e1d495c3faf4642b6ec1c4be8acc7cd5bc51d785/icons/obj/ammo.dmi, improvised ammo from https://github.com/tgstation/tgstation/ at commit fb2d71495bfe81446159ef528534193d09dd8d34",
     "states": [
         {
             "name": "base"
@@ -31,6 +31,12 @@
         {
             "name": "flare-spent"
         },
+        {
+            "name": "improvised"
+        },
+        {
+            "name": "improvised-spent"
+        },
         {
             "name": "incendiary"
         },