Datasource: Overhaul plugin error handling and action buttons (#67014)

* - initial work on data source config page

* - add links to test status box
- add tracking function

* - add test for the DataSourceConfigAlert component

* - fix flicker of the alert box

* - fix the build

* - small improvements

* - fix failing build

* - fix failing unit tests

* - prettier and betterer fixes

* - fix failing e2e tests

* - fix build again

* - rewrite solution according to the PR comments

* - cleanup

* - fix failing e2e

* - use absolute path in link

* Minor fixes

---------

Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

public/app/plugins/datasource/dashboard/datasource.ts

@@ -1,4 +1,10 @@
-import { DataSourceApi, DataQueryRequest, DataQueryResponse, DataSourceInstanceSettings } from '@grafana/data';
+import {
+  DataSourceApi,
+  DataQueryRequest,
+  DataQueryResponse,
+  DataSourceInstanceSettings,
+  TestDataSourceResponse,
+} from '@grafana/data';
 
 import { DashboardQuery } from './types';
 
@@ -18,7 +24,7 @@ export class DashboardDatasource extends DataSourceApi<DashboardQuery> {
     return Promise.reject('This should not be called directly');
   }
 
-  testDatasource() {
-    return Promise.resolve({});
+  testDatasource(): Promise<TestDataSourceResponse> {
+    return Promise.resolve({ message: '', status: '' });
   }
 }