Implement DB interface required by LOCODE validator on new wrapper over the
LOCODE Bolt DB (Record on new wrapper over LOCODE Bolt DB entries).
Construct LOCODE validator and pass it to Netmap processor's constructor as
NodeValidator parameter.
Thus, candidates for a network map must set LOCODE attribute for which there
is an entry in the NeoFS location database.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
