Maintain an invariant that any blobovnicza is present either
in `opened` or in `active` map. Otherwise, the logic becomes too
complicate because it is not obvious when we should close the blobovnicza.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
1. Move compression parameters to the `shard` section.
2. Allow to use multiple sub-storage components in the blobstor.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Allow to extend blobstor with more storage sub-systems. Currently
objects stored in the FSTree have empty byte slice descriptor and object
from blobovnicza tree have the same id as earlier. Each such change in
the identifier formation should be accompanied with metabase version
increase.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
