Add calibration sources required by METIS

[teutoburg]

Adds a basic pinhole mask on the basis of the already existing one for MICADO (and using the positions defined in #31), as well as a basic flat-field laser spectrum source.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 79.59%. Comparing base (fb9baa2) to head (b904a09).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev_master #80 +/- ## =========================================== Coverage 79.59% 79.59% =========================================== Files 44 44 Lines 2049 2049 =========================================== Hits 1631 1631 Misses 418 418 ```

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[teutoburg]

Also closes #31 (once complete)

[hugobuddel]

Just a note that https://github.com/AstarVienna/METIS_Simulations/issues/11 contains a figure of the spectrum with about 20 lines from the variable laser (if I interpret the figure correctly). So maybe we can also do about 20 lines by default (I recall I suggested about 10 before; that number was just pulled out of thin air). We would probably need to make the simulations to decide what the best setting of the laser would be.

Please tag me if you need specific input from me @teutoburg . I trust you to decide when this can be merged.

[teutoburg]

Just a note that AstarVienna/METIS_Simulations#11 contains a figure of the spectrum with about 20 lines from the variable laser (if I interpret the figure correctly). So maybe we can also do about 20 lines by default (I recall I suggested about 10 before; that number was just pulled out of thin air). We would probably need to make the simulations to decide what the best setting of the laser would be.

For some bizarre reason, anything above 6 lines results in, ... 2 lines. I've looked at it for a bit now and not sure why this is happening. Maybe they get too close together and that confuses Synphot? But I don't see why that might happen...

[teutoburg]

For some bizarre reason, anything above 6 lines results in, ... 2 lines. I've looked at it for a bit now and not sure why this is happening. Maybe they get too close together and that confuses Synphot? But I don't see why that might happen...

Nevermind, this was more float madness.....

[teutoburg]

I'll merge as soon as tests pass...