When application is being terminated, replicator routine
might be on the object picking phase. Storage is terminated
asynchronously, thus `Select()` may return corresponding
error. If we don't process `context.Done()` in this case,
then application freezes on shutdown.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
Implement Policer service that performs background work to check compliance
with the placement policy for local objects in the container. In the initial
implementation, the selection of the working queue of objects is
simplified, and there is no transfer of the result to the replicator.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
