Adds stair entities (with new sprites,) nukes stair decals (#20279)

* nukes stair decals, adds entity stairs

* FUCK. my furniture

* fix deprecated sprites

Resources/Textures/deprecated.rsi/meta.json

@@ -0,0 +1,14 @@
+{
+    "version": 1,
+    "license": "CC0-1.0",
+    "copyright": "Made by Flareguy for Space Station 14",
+    "size": {
+        "x": 32,
+        "y": 32
+    },
+    "states": [
+        {
+            "name": "deprecated"
+        }
+    ]
+}