Move documentation to hydrus

[chrizandr]

Instead of having separate repos for each project, we should add all documentation in the doc/ path into the hydrus repo. This way we build documentation directly with hydrus.

We should also implement the same things for other repos that need documentation.

[Mec-iS]

all autogenerated doc should be with the code. Also the one specific to a repo. The ecosystem-wide documentation should have its own place.

[chrizandr]

Right, but this repo doesn't really have ecosystem wide documentation right? I was under the impression that this is only documentation related to hydrus. In which case we should move it to hydrus.