how to properly handle the track options for the controller

[tudoroancea]

Basically, each ocp solver will be generated for one track and only one track. When we switch tracks, we have to switch controllers.

• Do we pre-generate controllers for all tracks and include them all ? => to be done properly, we would have to create some enums (maybe)
• do we generate them lazily by calling a python script? => would be hard to source the right env from c++

[tudoroancea]

We can actually make the casadi interpolant class parametric (see this constructor).
We can therefore only provide the grid points at generation time with

kappa_ref = interpolant("kappa_ref", "linear", [s_ref])

and define the dynamics using kappa_ref(s, kappa_ref_values) (instead of kappa_ref(s)) where kappa_ref_values is an SX/MX variable contained in the parameters of the AcadosModel.
These parameters then only have to be set at runtime using the function ihm2_fkin6_acados_update_params().

Only caveat: the grid itself can also be a parameter but the size is determined at generation time. We therefore had (for the moment) to sample a fixed number of points on the center line of each track (5000 per lap to have at most 10cm resolution for the longest FS tracks of 500m).