MAPG-103 implement saving on client side + server side skeleton

src/Controller/MapAdminController.php

@@ -49,7 +49,7 @@ class MapAdminController implements ISecured
         return new HtmlContent('admin/map_editor', $data);
     }
 
-    public function getPlace()
+    public function getPlace(): IContent
     {
         $placeId = (int) $this->request->query('placeId');
 
@@ -59,6 +59,16 @@ class MapAdminController implements ISecured
         return new JsonContent($data);
     }
 
+    public function saveMap(): IContent
+    {
+        $mapId = (int) $this->request->query('mapId');
+
+        //TODO
+
+        $data = ['added' => []];
+        return new JsonContent($data);
+    }
+
     private function getMapBounds(int $mapId): Bounds
     {
         $select = new Select(\Container::$dbConnection, 'maps');