Enable Pylint warning unused-import

[vachram97]

Contributes to #1295 (unused-import)

Changes made in this Pull Request:

• unused-import check was enabled for pylint
• unnecessary imports were removed
• 2 imports were shadowed since they are internal for library part

PR Checklist

• [x] Tests? some tests are skipped on local machine
• [x] Docs? no changes are needed to docs
• [x] CHANGELOG updated? as no new functionality/bug fixes were introduced, there is nothing to add to changelog
• [x] Issue raised/referenced?

Developers certificate of origin

• [x] I certify that this contribution is covered by the LGPLv2.1+ license as defined in our LICENSE and adheres to the Developer Certificate of Origin.

---

📚 Documentation preview 📚: https://mdanalysis--4518.org.readthedocs.build/en/4518/

[github-actions[bot]]

Linter Bot Results:

Hi @vachram97! Thanks for making this PR. We linted your code and found the following:

Some issues were found with the formatting of your code.

Code Location	Outcome
main package	⚠️ Possible failure
testsuite	⚠️ Possible failure

Please have a look at the darker-main-code and darker-test-code steps here for more details: https://github.com/MDAnalysis/mdanalysis/actions/runs/9726590606/job/26845212202

---

Please note: The black linter is purely informational, you can safely ignore these outcomes if there are no flake8 failures!

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 93.15%. Comparing base (cfa4438) to head (e28a2a9).

:exclamation: Current head e28a2a9 differs from pull request most recent head a76213f

Please upload reports for the commit a76213f to get more accurate results.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4518      +/-   ##
===========================================
- Coverage    93.60%   93.15%   -0.45%     
===========================================
  Files          171       12     -159     
  Lines        21235     1067   -20168     
  Branches      3933        0    -3933     
===========================================
- Hits         19876      994   -18882     
+ Misses         899       73     -826     
+ Partials       460        0     -460     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[orbeckst]

@RMeli can you please shepherd this PR? Thank you!

[orbeckst]

@vachram97 I edited your issue text so that we don't accidentally close the parent issue #1295 .

[orbeckst]

@vachram97 do you still have time to work on this PR? If so, please respond to the reviews.

[orbeckst]

I merged and accidentally removed a new import in transformations.py. I added it back in 4cbe32c70d9fa745f7f5f56df61a3818bd10a73a and hopefully that's now ok.

[vachram97]

I have updated the PR with all comments were addressed as requested and last version MDAnalysis/develop was merged into PR.

Tests fail on the testsuite/MDAnalysisTests/parallelism/test_multiprocessing.py test with time limit error and seems to be not related to this PR.

[RMeli]

@vachram97 I took the freedom to fix the conflicts for you, so that we can move forward and see how CI is faring.