Added GitHub Actions

[GiovanniBussi]

@sbottaro I added GitHub Actions and fixed tests.

Notes:

• mdtraj fixed the PDB format. This required resetting the tests
• nosetests is not compatible with python 3.10 and seems not maintained. I switched to pytest

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (master@db22173). Click here to learn what that means.
The diff coverage is 0.00%.

@@           Coverage Diff            @@
##             master     #48   +/-   ##
========================================
  Coverage          ?   0.00%           
========================================
  Files             ?      17           
  Lines             ?    3156           
  Branches          ?       0           
========================================
  Hits              ?       0           
  Misses            ?    3156           
  Partials          ?       0           

Impacted Files	Coverage Δ
barnaba/commandline.py	0.00% <0.00%> (ø)

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