Put Argus documentation on readthedocs

[katsel]

Argus documentation should be available on readthedocs.

argus.readthedocs.io is registered to a different project, so I suggest argus-server as a name (as on pypi).

Afterwards, point documentation links in the README to readthedocs.

[hmpf]

Existing rtd, not renamed: https://readthedocs.org/projects/aas/

I've applied to get the project slug changed, here: readthedocs/readthedocs.org#7696

[katsel]

Oh. Stumbled across another mini-issue that's related to this one.

The PyPI README has some broken links because it cannot find the docs/ folder there!

Let's count that as another reason to get readthedocs running, and use absolute links on the README.

[katsel]

• delete old rtd (aas)

• create argus-server rtd

• close Please change a specific project slug readthedocs/readthedocs.org#7696

• change the links on the README to the absolute URL on rtd

• update maintainers