Add selected navigation for organisations page

To match how the navigation works for a single service.

app/__init__.py

@@ -39,7 +39,7 @@ from werkzeug.local import LocalProxy
 from app import proxy_fix
 from app.config import configs
 from app.asset_fingerprinter import AssetFingerprinter
-from app.navigation import HeaderNavigation, MainNavigation
+from app.navigation import HeaderNavigation, MainNavigation, OrgNavigation
 from app.notify_client.service_api_client import ServiceAPIClient
 from app.notify_client.api_key_api_client import ApiKeyApiClient
 from app.notify_client.invite_api_client import InviteApiClient
@@ -93,6 +93,7 @@ current_organisation = LocalProxy(partial(_lookup_req_object, 'organisation'))
 navigation = {
     'main_navigation': MainNavigation(),
     'header_navigation': HeaderNavigation(),
+    'org_navigation': OrgNavigation(),
 }