Switch to Github Actions CI

[ehpor]

This PR moves CI from Azure Pipelines to Github Actions. This allows for tighter integration into the Github ecosystem. This also unifies the code between operating systems and reduces workload later on, since Actions are kept up to date by outsiders.

Todo:

• [x] Fix coverage upload.
• [x] Ensure that documentation artifacts look correct.
• [x] Ensure that documentation upload works.
• [x] Fix documentation version number.
• [ ] Change required Github checks.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.21%. Comparing base (037b3b6) to head (9ab9a7e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #226 +/- ## ========================================== + Coverage 82.05% 82.21% +0.15% ========================================== Files 101 102 +1 Lines 7552 7555 +3 ========================================== + Hits 6197 6211 +14 + Misses 1355 1344 -11 ```

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[ehpor]

@ivalaginja I'll change out the Github required checks after your review.

[ehpor]

Thanks! Changing the required checks now.