Remove author names from headers and tidy up for flake8 issues

[adybbroe]

This PR removes the author names from headers.
Now also urge contributors to add their name in the AUTHORS.md

While doing this I fixed many small code style issues upseting flake8.

• Closes #xxxx
• Tests added
• Tests passed: Passes pytest pyspectral
• Passes flake8 pyspectral
• Fully documented

[adybbroe]

@Plantain Perhaps you want to add your name to the AUTHORS.md file, you are welcome doing it here at least!

[codecov]

Codecov Report

Merging #163 (45e3bfe) into main (d36a108) will decrease coverage by 0.05%.
The diff coverage is 93.93%.

@@            Coverage Diff             @@
##             main     #163      +/-   ##
==========================================
- Coverage   89.08%   89.03%   -0.06%     
==========================================
  Files          22       22              
  Lines        2529     2516      -13     
==========================================
- Hits         2253     2240      -13     
  Misses        276      276              

Flag	Coverage Δ
unittests	89.03% <93.93%> (-0.06%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pyspectral/atm_correction_ir.py	81.35% <ø> (ø)
pyspectral/bandnames.py	100.00% <ø> (ø)
pyspectral/raw_reader.py	0.00% <0.00%> (ø)
pyspectral/tests/data.py	100.00% <ø> (ø)
pyspectral/tests/test_utils.py	98.00% <ø> (ø)
pyspectral/tests/unittest_helpers.py	71.42% <ø> (ø)
pyspectral/blackbody.py	79.46% <100.00%> (ø)
pyspectral/config.py	80.48% <100.00%> (ø)
pyspectral/near_infrared_reflectance.py	80.53% <100.00%> (-0.13%)	⬇️
pyspectral/radiance_tb_conversion.py	92.85% <100.00%> (-0.25%)	⬇️
... and 11 more

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[mraspaud]

LGTM, just one suggestion for Helge's name