How to include constraints in custom differential action models? #1205

We're refactoring deeply Crocoddyl. For instance, we'll deprecate differentiable action models in future releases. This constraint us to develop the requested example.

However, I suggest you have a look at our inverse-dynamics differential action models. In a nutshell, the constraint manager works similarly to our cost sum, i.e., you need to share the memory: https://github.com/loco-3d/crocoddyl/blob/devel/include/crocoddyl/multibody/actions/free-invdyn.hpp#L401