Draft: Handle multiple throughput options in a single job

Allow to run multiple throughput tests with different options as part of the same job. The idea is to be able to share the download and installation overhead between throughput tests of the same build, which is about 6 min per job.

Goes with lhcb-datapkg/PRConfig!308 (closed)

@sstahl @decianm @sponce @clemenci @rmatev

mentioned in merge request lhcb-datapkg/PRConfig!308 (closed)

closed