Add non-API documentation

[jix]

Setup a sphinx project for non-API documentation. Initially this will focus on internal documentation for developers covering topics for which the rustdoc generated API documentation isn't a good fit, but should eventually also include the end user documentation.

• setup a sphinx project with the yosyshq theme
• figure out at least some amount of rustdoc integration to make it feasible to link between the rustdoc API docs and sphinx docs in both directions

[chenbo-again]

Hi jix
I'm currently working on this, I find a crate named sphinx-rustdocgen, but It's not very stable for now, it crashed when I try to use it(for several package in the imctk workspace), should we try to recovery that?

[jix]

As far as I can tell, sphinx-rustdocgen enables using sphinx to create API documentation for a rust crate, while this issue is about using sphinx for non-API documentation and how to best link between that and a rustdoc generated API documentation. For the rust API documentation we want to continue using rustdoc.

At this point we do not have any non-API documentation, making it hard to tell what kind of integration between sphinx and rustdoc would be most useful. In that sense it is a bit too early to address that part of this issue.

Overall this project is still a relatively early work in progress and at the moment not well positioned for independent external contributions. Until we have more of a contribution process in place and sufficient documentation to give all the required context, I would recommend reaching out and discussing any issue before starting to work on it.