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/Misc/modular_receiver.rsi/meta.json

@@ -0,0 +1,22 @@
+{
+  "version": 1,
+  "license": "CC-BY-SA-3.0",
+  "copyright": "Taken from https://github.com/tgstation/tgstation at commit 6665eec76c98a4f3f89bebcd10b34b47dcc0b8ae. Inhands sprited by Flareguy for Space Station 14.",
+  "size": {
+    "x": 32,
+    "y": 32
+  },
+  "states": [
+    {
+      "name": "icon"
+    },
+    {
+      "name": "inhand-left",
+      "directions": 4
+    },
+    {
+      "name": "inhand-right",
+      "directions": 4
+    }
+  ]
+}