Cf tests ci
Major change:
This adds a test stage to the ci pipeline. Please note that this test will fail since one of the tests fails (see #1 (closed))
Other changes:
- job for building wheel (tests will run on wheel and not on local files)
- moved building of docs to pages job to speed up build stage
- added rules to only upload to PyPi if setup.py changed (i.e. version was incremented)
- added pip package caching to pipeline
- added exiftool as tests depend on it
- added expiration rules to artifacts