Snap to nearest cardinal on traversal (#10869)

Content.Shared/Decals/DecalPrototype.cs

@@ -10,5 +10,10 @@ namespace Content.Shared.Decals
         [DataField("sprite")] public SpriteSpecifier Sprite { get; } = SpriteSpecifier.Invalid;
         [DataField("tags")] public List<string> Tags = new();
         [DataField("showMenu")] public bool ShowMenu = true;
+
+        /// <summary>
+        /// If the decal is rotated compared to our eye should we snap it to south.
+        /// </summary>
+        [DataField("snapCardinals")] public bool SnapCardinals = false;
     }
 }