Add basic teleportation and portals (#269)

* Add basic teleportation and portals

* Address PJB's feedback and minor cleanup

Content.Shared/GameObjects/Components/Movement/SharedTeleporterComponent.cs

@@ -0,0 +1,48 @@
+using System;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Map;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Movement
+{
+    public enum ItemTeleporterState
+    {
+        Off,
+        Charging,
+        On,
+        Cooldown,
+    }
+
+    public enum TeleporterType
+    {
+        Directed,
+        Random,
+        Beacon,
+    }
+
+    [NetSerializable]
+    [Serializable]
+    public enum TeleporterVisuals
+    {
+        VisualState,
+    }
+
+    [NetSerializable]
+    [Serializable]
+    public enum TeleporterVisualState
+    {
+        Ready,
+        Charging,
+    }
+
+    [Serializable, NetSerializable]
+    public class TeleportMessage : ComponentMessage
+    {
+        public readonly GridCoordinates Target;
+
+        public TeleportMessage(GridCoordinates target)
+        {
+            Target = target;
+        }
+    }
+}