Update readme and docs

[szabo137]

This updates the readme and docs adopting the current iteration on the implementation of the interface.

After merging, I would like to prepare a release and register the package.

Related issues

Closes #25

Checklist

• write the tutorials for four-vectors
• write the tutorials for coordinate systems
• rewrite the description of the interface (clarification and opting out parts to the other doc sections)
• Tests are passing
• Docs were updated and workflow is passing

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.38%. Comparing base (cf892a6) to head (390ca90).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #26      +/-   ##
==========================================
- Coverage   93.91%   93.38%   -0.54%     
==========================================
  Files           4        5       +1     
  Lines         148      136      -12     
==========================================
- Hits          139      127      -12     
  Misses          9        9              

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[szabo137]

Many thanks for the comments. I addressed all of them. Please reply or resolve 😸

[AntonReinhard]

No further comments from me, but I can't resolve my earlier comments for some reason. Feel free to resolve them yourself.

[mmikhasenko]

I've looked over all files in this PR (just did not review the new tutorials well).

It looks good, a lot of improvements, I vote for getting this PR merged