Replace redis dependency?

[spacebear21]

Redis moved to closed-source and the rust crate is being disputed. redis-rs/redis-rs#1419

[DanGould]

valkey is the obvious candidate that comes to mind.

[0xBEEFCAF3]

I would put my vote in for sled. Its simple to work with and fast.

[DanGould]

Unfortunately sled hasn't been maintained for 2 years which I reasoned was OK for payjoin-cli since it's a bit of a demo tool, but probably not ok for the aspirationally production-hardened payjoin-directory.

Redb is an alternative I hear come up a lot for sled, but no modern version of it complies with our MSRV. Now, I'd be ok bumping MSRV just for payjoin-directory but NOT for the payjoin crate. Not sure how much trouble multiple crates with different MSRV would be for our repo.