REFACTOR: Architecture to match pyansys guide lines

[SMoraisAnsys]

This PR is a huge refactoring of the code base. It includes the following changes:

1. move the code from pyaedt to src/ansys/aedt/core;
2. duplicate the files of src/ansys/aedt/core in src/pyaedt to allow users to keep being able to do import pyaedt;
3. rename files to follow PEP8 convention on module names and harmonize with other python files;
4. change build system from flint to setuptools to allow building while having 2. working correctly (otherwise, only one target can be used)

Note: a warning is now triggered when one does import pyaedt so that every user is aware of this changes. On top of that, the renaming of the files shouldn't be impacting users as we are doing 2 and 4 at the same time. This way, old filenmaes will temporarily remain available as aliases pointing to the newly renamed files, ensuring temporary backward compatibility.

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[codecov]

Codecov Report

Attention: Patch coverage is 97.74127% with 11 lines in your changes missing coverage. Please review.

Project coverage is 82.87%. Comparing base (ca17b80) to head (1b49936).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4849      +/-   ##
==========================================
- Coverage   83.51%   82.87%   -0.64%     
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  Files         122      124       +2     
  Lines       54975    55417     +442     
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+ Hits        45910    45925      +15     
- Misses       9065     9492     +427