QueryTypes: Add feature toggle to show query types in datasource apiservers (#88213)

* initial attempt

* show query types

* show query types

* with formatting

* with formatting

* more cleanup

* add feature toggle

* fix build

pkg/tsdb/grafana-testdata-datasource/kinds/query.go

@@ -172,7 +172,7 @@ type USAQuery struct {
 //go:embed query.types.json
 var f embed.FS
 
-// QueryTypeDefinitionsJSON returns the query type definitions
-func QueryTypeDefinitionsJSON() (json.RawMessage, error) {
+// QueryTypeDefinitionListJSON returns the query type definitions
+func QueryTypeDefinitionListJSON() (json.RawMessage, error) {
 	return f.ReadFile("query.types.json")
 }