* fix: ensure that query tokio background tasks are canceled
While I am not entirely sure if this explains some of the memory leaks I
am seeing in prod, not canceling the tasks correctly certainly makes
debugging way harder and also renders certain form of throttling (e.g.
max. concurrent queries) somewhat ineffective.
Note that parquet file downloads are currently NOT canceled because
tokios `spawn_blocking` cannot be canceled.
* refactor: `Vec` -> `Option`
* refactor: `spawn_blocking` creates a join handle, even though it is useless
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>
* ci: fix cargo deny
* chore: downgrade `socket2`, version 0.4.5 was yanked
* chore: rename `query` to `iox_query`
`query` is already taken on crates.io and yanked and I am getting tired
of working around that.