It may be required to evacuate only objects or only tree or all, so
now it spossible to specify.
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
Now it's possible to run evacuate shard in async.
Also only one evacuate process can be in progress.
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>