5123: Fix batch details r=dureuill a=irevoire
# Pull Request
## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/5079
Fixes https://github.com/meilisearch/meilisearch/issues/5112
## What does this PR do?
- Make the processing tasks actually processing in the stats of the batch instead of enqueued
- Stop counting one extra task for all non-prioritized batches in the stats
- Add a test
Co-authored-by: Tamo <tamo@meilisearch.com>
5094: Implement a bbqueue channel between the extractors and the writer r=dureuill a=Kerollmops
This PR switches from a bounded crossbeam channel only with allocated entries for the communication between the extractors and the writer to a [BBQueue](https://github.com/jamesmunns/bbqueue)-based system with a Single Producer Single Consumer kind of Circular/Ring Buffers channel.
- [x] Implement the BBQueue channel system...
- [x] with a crossbeam channel to wake up the receiver.
- [x] Manage the BBQueue allocated memory dynamically.
- [x] Support content that doesn't fit in the bbqueues.
Co-authored-by: Clément Renault <clement@meilisearch.com>
