rework dimensions and orientation into Placement, optimise requirements to work on previous candidates, use vec3 for positions

Assets/Engine/Runtime/Orientation.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+
+namespace EscapeRoomEngine.Engine.Runtime
+{
+    public enum Orientation
+    {
+        North = 0, East = 90, South = 180, West = 270
+    }
+
+    public static class OrientationExtensions
+    {
+        public static HashSet<Orientation> EveryOrientation() => new(new[]
+        {
+            Orientation.North, Orientation.East, Orientation.South, Orientation.West
+        });
+
+        public static float Angle(this Orientation orientation) => (float)orientation;
+    }
+}