LayerServer: add opt-out to get counted for some irrelevant layers, remove some obsolete 'cluster' information

assets/layers/summary/summary.json

@@ -2,7 +2,6 @@
   "id": "summary",
   "description": "Special layer which shows `count`",
   "source": "special",
-  "name": "CLusters",
   "title": {
     "render": {"en": "Summary"}
   },

assets/layers/walls_and_buildings/walls_and_buildings.json

@@ -31,6 +31,7 @@
   ],
   "minzoom": 18,
   "shownByDefault": false,
+  "isCounted": false,
   "title": {
     "render": {
       "en": "Wall or building",