Support RFC 1912 checks

[rafi0101]

Would be nice if your script powerdns_record.py supports some rfc checks.

For example:
You are not allowed to create an A and CNAME record for one subdomain.

Maybe you can add this check, and some other common configuration error checks.
Because PowerDNS API is not supporting any of this checks.

see: https://tools.ietf.org/html/rfc1912#section-2.4

[Nosmoht]

Hi @rafi0101,

sorry for the late response. I am not working with PowerDNS anymore since several years. So, if you want some checks -> feel free to send a PR. Contribution is always welcome.