Openapi integration

[st3b1t]

hi,

I was trying to figure out what is the primary source in from which the documentation is generated, is it the reference/*.rst files in this repository?

I would like to implement(in a PR) some new build commands for example: make json generate json-schema make yaml generates a yaml file following the OpenApi specs.

I think these are two very important things for integrating rpc interfaces with other services or software that need APIs from bitcoin nodes as a data source. this would also make the generation of technical documentation much more usable through use of tools like Swagger. It would also make it easier CI on the Rest RPC API of bitcoin core.

I am open to suggestions