Schema change

After the recent addition of the disabled field in the default database schema I see no longer a reason for maintaining two separate database schemes, and sets of queries (nondnssec and dnssec).

This pull add all dnssec related fields to the default schema. These fields are ignored if there is no [backend]-dnssec=yes in the configuration. There is no need to rectify until the dnssec switch is enabled, and even if dnssec is global enabled, only domains with keys need rectify.

As extra all (non dnssec) metadata options are available in non dnssec mode.