Make laser parameters configurable; utility function for tunable laser

[oczoske]

The laser parameters (wavelength, power) are now taken from wcu.meta, i.e. from a config file or from kwargs.
All parameters can be changed by doing, e.g.

wcu = metis['wcu_source']
wcu.meta['laser_l_wave'] = 3.15
wcu.set_lamp("laser")

set_lamp is necessary to recompute the lamp emission.

The wavelengths of the tunable laser should be more easily accessible to the user, therefore a utility method is offered (this recomputes the emission automatically):

wcu.tune_laser(wavelength=np.linspace(4.68, 4.78, 10))

A validation method for the wavelengths has been implemented but is not yet used as we do not have reliable information on the actually available wavelength range.

[codecov]

Codecov Report

❌ Patch coverage is 94.73684% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.35%. Comparing base (5b85425) to head (1e4c727).
⚠️ Report is 42 commits behind head on main.

Files with missing lines	Patch %	Lines
scopesim/effects/metis_wcu/metis_wcu.py	94.73%	2 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #970 +/- ##
==========================================
+ Coverage 75.89% 76.35% +0.46% 
==========================================
Files 70 69 -1 Lines 9030 9086 +56 ==========================================
+ Hits 6853 6938 +85 + Misses 2177 2148 -29 

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[teutoburg]

See individual comments, but overall fine.