REFACTOR: Conftest refactoring and local_config cleaning

[eblanco-ansys]

Description

• Removed unused and outdated local config parameters
• Unified conftest files. Now there all the common configs are nested stating from tests/conftest.py
• Removed a lot of redundant code

Missing

• Add docs section explain local_config.json parameters

Issue linked

#6474

Checklist

• I have tested my changes locally.
• I have added necessary documentation or updated existing documentation.
• I have followed the coding style guidelines of this project.
• I have added appropriate tests (unit, integration, system).
• I have reviewed my changes before submitting this pull request.
• I have linked the issue or issues that are solved by the PR if any.
• I have agreed with the Contributor License Agreement (CLA).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.49%. Comparing base (628c68e) to head (84ad71b).

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #6727       +/-   ##
===========================================
- Coverage   83.23%   44.49%   -38.74%     
===========================================
  Files         245      245               
  Lines       77361    77361               
===========================================
- Hits        64389    34420    -29969     
- Misses      12972    42941    +29969     

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