Resolve "Add OSKAR compilation step to CI/CD"
Compile and install OSKAR in CI/CD stage (both cpp and python).
The validity of the OSKAR installation checked by https://git.astron.nl/RD/EveryBeam/-/blob/30-oskar-compile-ci-cd/.gitlab-ci.yml#L82, i.e. python -c "import oskar"
.
(Comparison) tests can be readily plugged-in
Closes #30 (closed)