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/promlib/models/query.go

@@ -434,6 +434,6 @@ func AlignTimeRange(t time.Time, step time.Duration, offset int64) time.Time {
 var f embed.FS
 
 // QueryTypeDefinitionsJSON returns the query type definitions
-func QueryTypeDefinitionsJSON() (json.RawMessage, error) {
+func QueryTypeDefinitionListJSON() (json.RawMessage, error) {
 	return f.ReadFile("query.types.json")
 }