Add Python API

[thomaslepoix]

Fixes #37

The test consist of a small Python example script from official tutorials, adapted to use OpenEMSH through its Python API.
The default logic relying on the SmoothMeshLines() function is still available to run.

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Trying instructions:

• First, build all the tools:

  export NIXPKGS_ALLOW_UNFREE=1
  nix develop '.#openems' --impure

• Run the script in legacy mode. When AppCSXCAD pop up, you can switch to Parallel Perspective [PP] and observe the mesh. Then, at the end of the simulation, take a look to the results.

  	nixGL test/Simple_Patch_Antenna.py

• Run the script with OpenEMSH, save the mesh, close, and observe the results looks similar:

  	nixGL test/Simple_Patch_Antenna.py openemsh

[sonarqubecloud]

Quality Gate failed

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud