DMARC entry is not allowed to have both "rf=afrf:iodef"

Summary

A DMARC entry is not allowed to have both settings "rf" set at once "afrf" and "iodef"

Steps to reproduce

1. Create a DMARC entry
2. Set both options to checked
3. Entry in DNS will have "af=afrf:iodef"

Correct behaviour

Only one of the values are allowed.

Environment

Server OS + version: Debian

ISPConfig version: 3.2.11p2

Proposed fix

To fix this it sould be solved by using a radio button and background logic.

References

Fixing this should make the other issue opsolete #6719