[CI] Run nightly calibration with new healthsystem mode

[giordano]

This turn the old calibration workflow into a reusable workflow, which can be used by multiple healthsystem modes runs.

This will eventually fix #1335.

As discussed in the meeting this morning we will probably go with a single larger machine (Standard_F32s_v2?), to answer the question at #1335 (comment).

TODO:

• reference mode name in WORKTREE_PATH and ENV, so that the different calibration runs don't step on each other (especially the cleanup stage)
• the run script should actually do something different for the two different modes (right now I don't know exactly where this should happen)
• set up and provision the new virtual machine. Remember to change the labels of the runners, some (10?) runners will be only for mode1, other only for mode2 (but both for tasks), and one for postprocess
• change the runs-on to use the new machine name
• the postprocessing script will have to be adapted
• the html generating script will have to be adapted
• drop the test commit before merging
• ...