ctdb-recovery: Replace use of ctdb_dbid_map with local db_list

ctdb-recovery: Replace use of ctdb_dbid_map with local db_list

This will be used to build a merged list of databases from all nodes,
allowing the recovery helper to create missing databases.

It would be possible to also include the db_name field in this
structure but that would cause a lot of churn.  This field is used
locally in the recovery of each database so can continue to live in
the relevant state structure(s).

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14294

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>