Move meta resync into CLI command

[roman-khimov]

Is your feature request related to a problem? Please describe.

I'm always frustrated when I think of metabase resynchronization. Currently it's done via resync_metabase configuration flag, but:

• it requires configuration modifications to use
• it's performed sequentially for shards which is slow (Parallel shard init #3416)
• it's very easy to forget about it once resync is done since it can take quite a lot of time leading to unplanned resync on the next start
• it's harder to track its state if something goes wrong since the node would just start normally

Describe the solution you'd like

1. Drop configuration (it's not used normally, so not a problem to do this immediately).
2. Move resync into lens meta resync which can take a blobstor and metabase file as parameters (don't forget about shard IDs).

This allows to run as many resynchronizations as needed in separate processes with clear result for each of them.