Indexing tooling via oak-run

To enable better management for indexing related operation specially around reindexing indexes on large repository setup we should implement some tooling as part of oak-run

The tool would support

1. For DocumentNodeStore setup it would be possible to connect oak-run to a live cluster and it would take care of indexing -> storing index on disk -> merging index -> importing it back at end. This would ensure that live setup faces minimum disruption and is not loaded much
2. For SegementNodeStore setup it would be possible to index on a cloned setup and then provide a way to copy the index back

Future Enhancements

1. Resumable tarversal - It should be able to reindex large repo with resumable traversal such that even if indexing breaks due to some issue it can resume from last state (OAK-5833)
2. Multithreaded traversal - Current indexing is single threaded and hence for large repo it can take long time. Plan here is to support multi threaded indexing where each thread can be assigned a part of repository tree to index and in the end the indexes are merged