Fix cli bug, cleanup and enhancement

[naik-aakash]

Closes #254

Todo

• [×] Add test with poscar.lobster
• [×] Add option for spin-polarized plots in cli for automatic analysis

[codecov]

Codecov Report

Attention: Patch coverage is 96.22642% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 97.41%. Comparing base (320fec0) to head (275168d).
Report is 1 commits behind head on main.

Files	Patch %	Lines
lobsterpy/cli.py	95.91%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #256      +/-   ##
==========================================
- Coverage   97.51%   97.41%   -0.11%     
==========================================
  Files          12       12              
  Lines        2700     2669      -31     
==========================================
- Hits         2633     2600      -33     
- Misses         67       69       +2     

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[JaGeo]

I will test it tonight when you say it is okay ;). Then, I will release a new version.

[JaGeo]

Works fine!