Decal Placer + add new decals for mapping (#6548)

* abomination

* okay its less unabashedly garbage now

* other UI changes

* its britney bitch

* proper greyscale full/half/quarter tiles

* misc cleanup

* rsi

* Add a palette system. It's Kara's problem now.

* oops

* a

* Departmental palette alpha tweaks

* oopy

* so true

* Update Content.Shared/Decals/ColorPalettePrototype.cs

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* fixes for that

* neutral light color and new warning lines

* dirt

* checkerboards

* oop

Co-authored-by: moonheart08 <moonheart08@users.noreply.github.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Resources/Textures/Decals/Overlays/greyscale.rsi/meta.json

@@ -0,0 +1,44 @@
+{
+  "version": 1,
+  "license": "CC-BY-NC-SA-3.0",
+  "copyright": "mirrorcult",
+  "size": {
+    "x": 32,
+    "y": 32
+  },
+  "states": [
+	{
+      "name": "fulltile_overlay"
+    },
+    {
+      "name": "halftile_overlay"
+    },
+    {
+      "name": "halftile_overlay_90"
+    },
+    {
+      "name": "halftile_overlay_180"
+    },
+    {
+      "name": "halftile_overlay_270"
+    },
+    {
+      "name": "quartertile_overlay"
+    },
+    {
+      "name": "quartertile_overlay_90"
+    },
+    {
+      "name": "quartertile_overlay_180"
+    },
+    {
+      "name": "quartertile_overlay_270"
+    },
+    {
+      "name": "checkerNESW"
+    },
+    {
+      "name": "checkerNWSE"
+    }
+  ]
+}