ipatests: add a test for ZSK/KSK keytype in DNSKEY record
When DNS is enabled for a zone, 2 DNSKEYs should be created:
one KSK and one ZSK.
Add a test ensuring that they can be queried on the master and
the replica.
Related: https://pagure.io/freeipa/issue/8647
Reviewed-By: Rob Crittenden <rcritten@redhat.com>