Move slit to MICADO.yaml; general spec mode

[oczoske]

The MICADO slit selection is moved to MICADO.yaml in the form of a SlitWheel:

• Makes it easier to introduce new slits (shifted slits, pinhole slits)
• Enables through-slit imaging.

A new mode SPEC is introduced, which replaces all current spectroscopic modes. The old modes SPEC_15000x20 etc. still exist and should work as before with default settings as indicated by their name.

FITS keyword INS.SLIT.NAME is updated when the slit is changed. As the pipeline relies on the names being "Short", "Wide", "Long", the slit definition files are renamed accordingly:

• 15000x20 -> Long
• 15000x20_offset -> Long_offset
• 3000x16 -> Short
• 3000x16_offset -> Short_offset
• 3000x48 -> Wide
• 3000x48_offset -> Wide_offset
  Again, the old modes keep their name.

A new notebook demonstrating the new slit mode has been added to MICADO/docs/extra_notebooks. Maybe this could be integrated with 6_basic_spectroscopy.ipynb, but I'll leave it stand-alone for now. Notebooks in the new directory extra_notebooks are not automatically run by github actions.

Needs AstarVienna/ScopeSim#875
Closes #88

[teutoburg]

I suggest adding

  sub_pixel:
    flag: True

to the default.yaml at the bottom.

While not strictly related to the rest of this PR, it seems like a useful default and doesn't appear to impact performance too badly, at least on my machine...

[oczoske]

Sorry for all those commits (from rebasing dev_master). The relevant commits for this PR are the first ones up to 5b96512 ("New notebook...")

[teutoburg]

Fixed the rebase accident as discussed through other means of communication. Ready to merge for me.

[janusbrink]

Thanks - this looks great. The pipeline relies on slit names "Long/Short/Wide" (and their pinhole/shifted variants) - so best to change the files/names to match before merging this change?