CI: Add template for pull request

[SMoraisAnsys]

As title says.

On top of helping to clarify the PR changes, objective, scope, ... Contributors are asked to agree with the CLA.

Note: the current CLA part might need some modifications as it should be performed only if someone has never agreed to it and isn't an Ansys employee.

[ansys-reviewer-bot]

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[SMoraisAnsys]

@MaxJPRey Can you give me your feedback on these changes ? I'd like to know if something new associated to the CLA as been performed or if we could add it to the project's PR template.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.67%. Comparing base (91543ea) to head (b2d91bb).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5453      +/-   ##
==========================================
- Coverage   84.67%   84.67%   -0.01%     
==========================================
  Files         143      143              
  Lines       60082    60082              
==========================================
- Hits        50875    50872       -3     
- Misses       9207     9210       +3     

[MaxJPRey]

@SMoraisAnsys Nothing new yet about the CLA.
The content of this PR is good.