Update API docs for v2

[ChrisSchinnerl]

No description provided.

[ChrisSchinnerl]

@n8maninger I feel like we had that discussion somewhere already but since we broke a good chunk of the API for v2 I wanted to know how you feel about biting the bullet and introducing an openapi specification in the repo for generating the docs.
It would be nice for similar reasons as knope. Being able to update the spec atomically within the same PR that introduces it is a huge upside imo.

[pcfreak30]

TBH I would +1 this as well, as it would help on interop/adoption. Anyone who wants to create a sia client library can honestly get most of it done via openapi generators and maintain those without needing to do a lot of CRUD R&D on http requests.

I have made Lumes portal API's OpenAPI 1st for the most part, for this reason, and consume the APIs as well.