PanelData: Adds annotations and QueryResultMeta dataTopic (#27757)

* topics round two

* more props

* remove Data from enum

* PanelData: Simplify ideas a bit to only focus on the addition of annotations in panel data

* Test data scenario

* Old graph panel showing annotations from PanelData

* Fixed comment

* Fixed issues trying to remove use of event.source

* Added unit test

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

pkg/tsdb/testdatasource/scenarios.go

@@ -277,6 +277,14 @@ func init() {
 		},
 	})
 
+	registerScenario(&Scenario{
+		Id:   "annotations",
+		Name: "Annotations",
+		Handler: func(query *tsdb.Query, context *tsdb.TsdbQuery) *tsdb.QueryResult {
+			return tsdb.NewQueryResult()
+		},
+	})
+
 	registerScenario(&Scenario{
 		Id:   "table_static",
 		Name: "Table Static",