Alerting: Fetch all applied alerting configurations (#65728)

* WIP

* skip invalid historic configurations instead of erroring

* add warning log when bad historic config is found

* remove unused custom marshaller for GettableHistoricUserConfig

* add id to historic user config, move limit check to store, fix typo

* swagger spec

pkg/services/ngalert/api/authorization_test.go

@@ -49,7 +49,7 @@ func TestAuthorize(t *testing.T) {
 		}
 		paths[p] = methods
 	}
-	require.Len(t, paths, 45)
+	require.Len(t, paths, 46)
 
 	ac := acmock.New()
 	api := &API{AccessControl: ac}