Checkzone functionality

[alexkiousis]

Figure out a way to implement running checks on zones and providing feedback from the UI.

[email protected]..:/var/log# pdnssec check-zone f.e.c.2.8.4.6.0.1.0.0.2.ip6.arpa                                      
May 15 13:18:23 [bindbackend] Done parsing domains, 0 rejected, 0 new, 0 removed
[Error] Following record had a problem: 4.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0..f.e.c.2.8.4.6.0.1.0.0.2.ip6.arpa IN PTR ixpbilling.gr-ix.gr
[Error] Error was: DNSPacketWriter::xfrLabel() found empty label in the middle of name
Checked 18 records of 'f.e.c.2.8.4.6.0.1.0.0.2.ip6.arpa', 1 errors, 0 warnings.