Frame extraction in the cluster using entry points

[sfmig]

Right now we manually edit the frame extraction script for the different jobs. With this PR we instead keep the bash script intact, and pass any required parameters as command line arguments.

Specifically, we would pass a config.json file that we would read and print to the logs. This way we keep track of what input parameters we passed but the bash script is not edited every time.

If the bash script is intact, then testing should be easier. I had a look at a few options for unit testing bash scripts:

• bats seems like a very nice tool for this. IIUC, it can be run in CI too.
• bach is another option, apparently all tests are --dry-run by default.
  • I don't fully get what they mean with "Because that unit tests should verify the behavior of bash scripts, not test commands."
  • I find the syntax a bit less user-friendly than bats (e.g., one test case in Bach is made up of two functions: one for running tests and one for asserting), but it may be a matter of familiarising oneself with it.
  • a blogpost on bach
• shunit2 is an alternative but seems less actively maintained (last release 2020) and the syntax seems a bit more cumbersome.

Any feedback or comments more than welcome!