add more information to existing errors logs and panics

- '$ROOT/$FILE' for better localization in the code
- add text where none was given
- fix unnecessary sprintf nesting in influxv2 and prometheus metricrepo logging

pkg/schema/job.go

@@ -133,12 +133,12 @@ const (
 func (e *JobState) UnmarshalGQL(v interface{}) error {
 	str, ok := v.(string)
 	if !ok {
-		return fmt.Errorf("enums must be strings")
+		return fmt.Errorf("SCHEMA/JOB > enums must be strings")
 	}
 
 	*e = JobState(str)
 	if !e.Valid() {
-		return errors.New("invalid job state")
+		return errors.New("SCHEMA/JOB > invalid job state")
 	}
 
 	return nil