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/markings.rsi/meta.json

@@ -0,0 +1,113 @@
+{
+  "version": 1,
+  "license": "CC-BY-SA-3.0",
+  "copyright": "tgstation at 606005645d3a14c4439e5ce14785650121b22678",
+  "size": {
+    "x": 32,
+    "y": 32
+  },
+  "states": [
+    {
+      "name": "arrows"
+    },
+    {
+      "name": "arrows_greyscale"
+    },
+    {
+      "name": "bot",
+    },
+    {
+      "name": "bot_greyscale",
+    },
+    {
+      "name": "bot_left",
+    },
+    {
+      "name": "bot_left_greyscale",
+    },
+    {
+      "name": "bot_right"
+    },
+    {
+      "name": "bot_right_greyscale"
+    },
+    {
+      "name": "box"
+    },
+    {
+      "name": "box_greyscale"
+    },
+    {
+      "name": "caution"
+    },
+    {
+      "name": "caution_greyscale",
+    },
+    {
+      "name": "delivery",
+    },
+    {
+      "name": "delivery_greyscale",
+    },
+    {
+      "name": "loading_area",
+    },
+    {
+      "name": "loading_area_greyscale"
+    },
+    {
+      "name": "standclear"
+    },
+    {
+      "name": "standclear_greyscale"
+    },
+    {
+      "name": "warn_box"
+    },
+    {
+      "name": "warn_box_greyscale"
+    },
+    {
+      "name": "warn_end"
+    },
+    {
+      "name": "warn_end_greyscale",
+    },
+    {
+      "name": "warn_full",
+    },
+    {
+      "name": "warn_full_greyscale",
+    },
+    {
+      "name": "warningline",
+    },
+    {
+      "name": "warningline_greyscale"
+    },
+    {
+      "name": "warninglinecorner"
+    },
+    {
+      "name": "warninglinecorner_greyscale"
+    },
+    {
+      "name": "warninglinecorner_flipped"
+    },
+    {
+      "name": "warninglinecorner_flipped_greyscale"
+    },
+    {
+      "name": "warn_corner"
+    },
+    {
+      "name": "warn_corner_greyscale"
+    },
+    {
+      "name": "warn_corner_flipped"
+    },
+    {
+      "name": "warn_corner_flipped_greyscale"
+    }
+  ]
+}