Improve compatibility with different visibility formats

[mpluess]

#620 changed the default visibility format to MS and improved / unified how visibilities are handled within Karabo.
However, the compatibility of simulators and imagers with the different visibility formats (currently two) needs to be improved or Karabo needs to be able to convert incompatible formats on-the-fly. See also this comment: #595 (comment)
Conversion of large visibility files can take a long time and potentially use a lot of storage. There are two options: do conversions only when specifically requested, e.g. via a flag, and raise exceptions by default when encountering an incompatible format, or automatically convert if needed and issue a warning to the user.
As Simon mentioned, conversion would ideally by implemented in a streaming fashion, i.e. without touching the disk.
When auto-converting, if the same file has been converted before, there should be a mechanism in place to reuse it and don't do unnecessary work. Requires checking if there have been changes to the original file since the last conversion.

• imager_rascil: support VIS to MS conversion @ create_dirty_image, create_cleaned_image, create_cleaned_image_variants
• imager_wsclean: support VIS to MS conversion @ create_dirty_image, create_cleaned_image
• InterferometerSimulation.__run_simulation_rascil: support MS to VIS conversion
• InterferometerSimulation.__run_simulation_long: support VIS output
• Visibility.combine_vis: support MS input
• Add newly supported combos to test_sim_format_imager_combos
• Remove temporary function karabo.test.util.get_compatible_dirty_imager

[sfiruch]

1 vote for "automatically convert if needed and issue a warning to the user."