I made some modifications and implemented a replica data migration tool
### Motivation We have a scenario where a large number of bookie nodes are offline, and we find that the bookie's offline solution is very time-consuming. Bookie offline steps are as follows: 1. Set the bookie node to be offline to readOnly; 2. Wait for the Pulsar data on the Bookie node to be offline to expire and delete; 3. When most of the data on these offline nodes is expired and cleaned up, there will still be some data that cannot be expired and deleted; 4. Stop a bookie, and then use the decommission command to migrate the data that has not been expired and cleaned up to the new node: bin/bookkeeper shell decommissionbookie -bookieid xx 5. When the data on one bookie node is migrated, continue to the next bookie node; Step 4 is very time-consuming. We found that waiting for a bookie data migration to complete, it takes about 1 hour, and we have 125 bookie nodes to be offline. ### Proposal To solve this problem, we developed a replica data migration tool. After having this tool, our offline steps are as follows: 1. Execute the data migration command: bin/bookkeeper shell replicasMigration --bookieIds bookie1,bookie2 --ledgerIds ALL --readOnly true 2. When the data migration is completed, stop all bookie nodes to be offline; In addition, this command can also migrate the replica data on some bookie nodes to other nodes, for example: bin/bookkeeper shell replicasMigration --bookieIds bookie1,bookie2 --ledgerIds ledger1,ledger2,ledger3 --readOnly false
