In the oak-segment-azure, reading the whole journal may be a time consuming task, as the blob appends are a bit slow to read. The
OAK-8604 introduces an improvement, by keeping the most recent journal entry saved as a metadata in the journal.log blob. We should allow to use this optimization in SegmentStoreMigrator, by adding a new migration parameter - onlyLastJournalEntry. This way, only the last entry in the journal will be migrated and it won't require to read the whole journal.