SA-BCM model introduction and cascade use-case refactoring

[mschouler]

This PR implements two major changes regarding the cascade use-case:

1. wolf input file and the adaptation script are hereby updated following the SA-BCM model implementation in wolf,
2. the folder structure is also reorganized (similarly to that of the NACA12 use-case) in order to include multiple folders : base, adap and mf.

Changes are also made to cascade_mesh.py in order to enhance the mesh parameterization.