Add RegionSystem.getWorldSpawn

Fix Warp
Update FixedRegionSystem

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/region/RegionSystem.java

@@ -42,6 +42,12 @@ public interface RegionSystem {
      */
     void save();
 
+    /**
+     * Returns the Location to teleport players to when they first join or Warp to "WorldSpawn"
+     */
+    @NonNull
+    Location getWorldSpawn();
+
     /**
      * Returns the GlobalRegion. This Region should have their {@link Region#getID()} return the
      * '00000000-0000-0000-0000-000000000000' UUID for easier retrieval with {@link #getRegion(UUID)}.