Feature Request: DNS Record Helpers

[semaja2]

It would be helpful to add some "helpers" for the various record types, for example PowerDNS-Admin project works in the below behaviour

1. Add new record, select record type (MX/CAA etc)
2. Select the content field for the record
3. A modal appears prompting for the various components (eg. Priority, Destination for MX)
4. Helper then compiles this into the string (eg. "0 mx1.example.com")

Whilst not super helpful with MX records, this would be more helpful for new comers for records like CAA who are not familair with the string required