[zarrs_zip] Investigate async compatible ways to do zip

[flying-sheep]

The zip crate isn’t really designed around e.g. accessing things over the network, and it shows in issues like zip-rs/zip2#231. TBF, that issue is fixed, but the zip crate is still designed around sync filesystem abstractions.

Feel free to close this if zip-over-network isn’t in-scope for zarrs_zip!

So far I’ve toyed around with

• rc-zip{-tokio,-sync}, which currently only does reading, but has the nicest API, so if it ever gains write support, that’s probably the one
• async_zip, which seems to work fine over the network, but I didn’t benchmark if it’s doing things smartly

[LDeakin]

Yes, this would be great @flying-sheep! async support has been a longstanding gap for the zip store. Both crates look like reasonable choices, and I'm not bothered about the first option being read-only. Writing to zip stores is a bit of a foot gun anyway since chunks cannot be amended.