Improve integration of OLI API CI workflows

[lbianchi-lbl]

The OLI API functionality is tested via external CI workflows, i.e. running outside of this public repository. This allows us to test a more complete set of features, however it results in a number of shortcomings:

• [x] Test coverage of the parts of the codebase that can only be tested in this way are not reported, causing the coverage to be underestimated
• [ ] The process currently requires workflow runs to be triggered manually

This issue is to track progress on improving the integration by addressing the points described above.

[lbianchi-lbl]

As a first (and possibly "good enough" in an 80/20 kind of way) solution, using the create commit status functionality in the GitHub API seems to work:

This doesn't address the coverage issue, but at least make it much easier to know the outcome of the CI workflow for a specific PR.

[adam-a-a]

As a first (and possibly "good enough" in an 80/20 kind of way) solution, using the create commit status functionality in the GitHub API seems to work:

This doesn't address the coverage issue, but at least make it much easier to know the outcome of the CI workflow for a specific PR.

Sounds like a good start (or "good enough finish").