Output rndc dnssec -status

Output rndc dnssec -status

Implement the 'rndc dnssec -status' command that will output
some information about the key states, such as which policy is
used for the zone, what keys are in use, and when rollover is
scheduled.

Add loose testing in the kasp system test, the actual times are
already tested via key file inspection.

(cherry picked from commit 19ce9ec1d4ac72b5e0858a80036289938d0796fd)