* added authenticate guard

* added metadata schema form, with the form model fields & validation and layout
* fixed the pagination for schemas and fields
* added reducer and actions for the registry state

src/app/+admin/admin-registries/metadata-schema/metadata-schema.component.ts

@@ -21,8 +21,9 @@ export class MetadataSchemaComponent implements OnInit {
   metadataFields: Observable<RemoteData<PaginatedList<MetadataField>>>;
   config: PaginationComponentOptions = Object.assign(new PaginationComponentOptions(), {
     id: 'registry-metadatafields-pagination',
-    pageSize: 10000
-  });
+    pageSize: 25,
+    pageSizeOptions: [25, 50, 100, 200]
+});
 
   constructor(private registryService: RegistryService, private route: ActivatedRoute) {