API: Add by UID routes for data sources (#29884)

- also add Get by UID+OrgID to datasource cache
- Refactor backend commands for Delete and Get to be unified

pkg/expr/service_test.go

@@ -106,7 +106,7 @@ func registerEndPoint(df ...*data.Frame) {
 	}
 
 	tsdb.RegisterTsdbQueryEndpoint("test", endpoint)
-	bus.AddHandler("test", func(query *models.GetDataSourceByIdQuery) error {
+	bus.AddHandler("test", func(query *models.GetDataSourceQuery) error {
 		query.Result = &models.DataSource{Id: 1, OrgId: 1, Type: "test"}
 		return nil
 	})

pkg/expr/transform.go

@@ -136,7 +136,7 @@ func QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.Que
 		datasourceID = req.PluginContext.DataSourceInstanceSettings.ID
 	}
 
-	getDsInfo := &models.GetDataSourceByIdQuery{
+	getDsInfo := &models.GetDataSourceQuery{
 		OrgId: req.PluginContext.OrgID,
 		Id:    datasourceID,
 	}