Clean up github actions

[francescalb]

It looks like installation of emmontopy happens several times in the ci and thus makes the testing unnecessarily slow. Check out and see if this ca be improved.

[CasperWA]

In my consideration, the only thing that needs to be updated at this point is to evaluate the ontodoc job - essentially cleaning it up and making sure to test the created outcome, if possible.

Also, the commented out lines in the tests job should be either removed or re-implemented either as part of the actual test suite or made into separate dedicated jobs with more post-introspection and assertions.