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>

Content.Client/Decals/UI/PaletteColorPicker.xaml

@@ -0,0 +1,12 @@
+<DefaultWindow xmlns="https://spacestation14.io"
+               Title="{Loc 'palette-color-picker-window-title'}"
+               MinSize="250 500"
+               SetSize="250 500">
+    <BoxContainer Orientation="Vertical">
+        <ItemList Name="PaletteList" VerticalExpand="True" Access="Public"/>
+        <BoxContainer Orientation="Horizontal">
+            <Label Text="Palette"/>
+            <OptionButton Name="Palettes"/>
+        </BoxContainer>
+    </BoxContainer>
+</DefaultWindow>