Add openapi schema and swagger ui

[ross-weir]

There was a WIP branch here for it: https://github.com/ChainCashLabs/chaincash-rs/tree/add-open-api

utopia seems like a decent package for it, the support for openapi in rust apps overall seems quite lacking so there will still be a heap of code/type definition duplication it seems

This utoipa extension package might lower the burden: https://github.com/ProbablyClem/utoipauto

Also consider api versioning: juhaku/utoipa#768
Discussion thread on axum: tokio-rs/axum#50

[sethdusek]

I would like to work on this.

[ross-weir]

I would like to work on this.

Nice, thanks!

To be clear, it would be great if we could automate generation of openapi stuff from our rust code. utoipa was one of the better libraries I could find for this in Rust but if you find something better that's cool

[mgpai22]

Can we please get this going @sethdusek @ross-weir