There was a request in If3dc95d1348553e5b43683f6a36d324fb978fbed to
make the role more generic so it could handle different layouts of
zone.db files. Make it so the role can take a list of tuples (domain,
path/to/zone.db) so that we can handle any layouts, and modify the
default searching to build this from the source directory.
Reviews in https://review.opendev.org/660888 suggested making this
defined as a generic job, so a validate-zone-db job is added.
Change-Id: I56cbc027f63787f90eef283eeb2fbb81486dcaf5
e6ca2e7c84