Add nightly regression tests for worker jobs

[daniel-wer]

Detailed Description

We should add nightly regression tests for the worker jobs on webknossos.org to make sure none of them is broken. Extra points for also testing the quality of the output, but this has less priority and will likely be a followup.

Context

• Specific to long-running jobs (set jobsEnabled=true in application.conf)
• Specific to webknossos.org (set isDemoInstance=true in application.conf)

Although the worker jobs are tested in voxelytics, their integration into webknossos using the most recent templates needs to be tested as well.