!per #3704 Persistence improvements

- Channel enhancements (#3773):
- Live read models (#3776):
- Batch-oriented journal plugin API (#3804):
- Batching of confirmations and deletions
- Message deletion enhancements (more efficient range deletions)
Merge pull request #1915 from krasserm/wip-3704-persistence-improvements-part-1-krassserm

!per #3704 Persistence improvement (part 1)