Add the ability to wait for documents to be published before responding to clients

[ChillFish8]

Elasticsearch provides a way to wait for indexing operations to be visible to searchers using the refresh=wait_for query parameter, it would be useful to have something similar in Quickwit waiting for the split containing the docs to be published especially for benchmarking.

I believe this will be something we'll need to do anyway for the ES-compatible API #2653

[fmassot]

@ChillFish8 seems like a duplicate of #2699

[ChillFish8]

It's similar but I don't think it's the same, that ticket describes forcing a commit/publish from what I can tell rather than just waiting for a publish to complete (which is what the refresh=wait_for parameter is on ES iirc)

[imotov]

I am actually trying to implement it both ways at the moment. It seems like if we force commit, we get wait_for functionality almost for free. I just ran into need for some preliminary plumbing that is needed in order to achieve that but I should get there soon. So, we can probably close this issue and track both variations on #2699.