Resolve "Schedule OSKAR comparison only once a week"
Closes #31 (closed), by running the OSKAR comparison stage (and the stages that are needed to run the comparison stage) once a week via a scheduled job.
See https://git.astron.nl/RD/EveryBeam/pipelines/2337.
If @tol and @offringa agree on this approach, we can merge and move https://jira.skatelescope.org/browse/AST-87 to "Done"