docs: ReadTheDocs builds fail due to pycurl

[tiborsimko]

After addition of pycurl, the ReadTheDocs builds fail with:

   FileNotFoundError: [Errno 2] No such file or directory: 'curl-config': 'curl-config'

This is most probably because some system dependencies such as libssl-dev and friends are not installed.

Investigate a best solution to fix the documentation builds.

• Perhaps add these libraries if RTD build system allows this?
• Perhaps use autodoc_mock_imports?

[ParthS007]

@tiborsimko this can be closed now?

[tiborsimko]

I thought of looking into generating the CLI API in other way... E.g. we could run click-sphinx locally and add the file into docs so that ReadTheDocs would simply consume it from there. (A bit like we are doing with OpenAPI stuff in REANA.) Hence I used addresses and not closes yet... I'll move the issue into "Ready for work" kanban column.

[tiborsimko]

Closing for v0.1.0 release, we can attack this later.