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>

plugins-bundled/internal/input-datasource/src/InputDatasource.ts

@@ -2,6 +2,7 @@
 import {
   DataQueryRequest,
   DataQueryResponse,
+  TestDataSourceResponse,
   DataSourceApi,
   DataSourceInstanceSettings,
   MetricFindValue,
@@ -68,7 +69,7 @@ export class InputDatasource extends DataSourceApi<InputQuery, InputOptions> {
     return Promise.resolve({ data: results });
   }
 
-  testDatasource() {
+  testDatasource(): Promise<TestDataSourceResponse> {
     return new Promise((resolve, reject) => {
       let rowCount = 0;
       let info = `${this.data.length} Series:`;