Add casacore and python-casacore to the build
The latest version of EveryBeam
requires Casacore >= 3.6, which is not available in any distribution (yet). So we need to build casacore
and python-casacore
ourselves now when building the Docker image.
This MR fixes the build, contains a few other improvements and some code clean up.
Closes RAP-909
Edited by Marcel Loose