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     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[teutoburg]

See individual comments, but overall fine.