[FluidDynamics] Refactor old compute_drag_process to compute flow forces & moments in body-fitted & embedded fluid formulations

[juancamarotti]

Summary

This PR refactors the existing compute_drag_process.py to support the computation of flow forces and moments instead of only flow forces (before wrongly called drag force). The new implementation works consistently for both body-fitted and embedded fluid formulations by relying on the existing flow force utilities in the FluidDynamicsApplication.

The previous drag-only functionality is preserved for backward compatibility through a deprecated wrapper, while the underlying implementation has been generalized to compute the full force and moment vectors about a user-defined reference point.

Additionally, a new Python process, compute_aerodynamic_coefficients_process.py, has been introduced. This process reuses the existing force and moment computation utilities and post-processes the results to output aerodynamic force and moment coefficients, based on user-provided reference area, reference chord, and dynamic pressure.

Main changes

• Refactored compute_drag_process to compute flow forces and moments.
• Added computation of moments about a reference point.
• Introduced compute_aerodynamic_coefficients_process for aerodynamic coefficient evaluation.
• Maintained backward compatibility with the previous drag process interface.

@rubenzorrilla

[juancamarotti]

Hi @rubenzorrilla, let's not forget this :)

Thanks!