[AAE-4966] Extensible app config (#6914)

* merge app config from the extensions

* improved service injection in unit tests

* extra unit test

* fix content tests

* update code as per review

* fix lint

* fix lint

* update code and tests

* update schema

lib/core/mock/search.service.mock.ts

@@ -59,5 +59,8 @@ export let searchMockApi = {
         queriesApi: {
             findNodes: () => Promise.resolve(fakeSearch)
         }
+    },
+    isEcmLoggedIn() {
+        return false;
     }
 };