[ExternalForcesAwareQP] Give the possibility to make the QP aware of external forces

[mathieu-celerier]

This PR allows the QP to be aware of the external forces and compensate for them to ensure all constraints and objectives. Compliance of a task, if necessary, is achieved by uncompensating the external forces by adding to the task's reference acceleration the accelerations produced by these external forces.

Detailed description of the additions

• [mc_rbdyn] Provide two new "sensors" implemented as devices: ExternalTorqueSensor & VirtualTorqueSensor
• [mc_tvm] Add information of ExternalTorqueSensor both as joint torque and acceleration in Robot with two new methods tauExternal() and alphaDExternal(). Add the update of external torque and acceleration as both output and update of TVM in Robot to prevent recomputation for multiple tasks with the updateEF() method.
• [mc_tvm] Modifies the DynamicFunction to include the compensation of external forces in b_ and a boolean in the constructor to activate or not this feature.
• [mc_solver] Modifies DynamicsConstraint, initialize, and initialize_tvm constructors to include a boolean that allows activation of the compensation feature by forwarding it to the DynamicFunction.
• [mc_tasks] Add two new compliant tasks CompliantPostureTask and CompliantEndEffectorTask to be used with this QP as it will naturally compensate external forces. Each task is a derivation of their non-compliant versions and adds getter and setter as well as datastore entries to control if a task should be compliant or not. Compliance for the tasks is achieved by adding the acceleration due to the external forces to the reference acceleration of the task.

[mathieu-celerier]

Need some fixes for now, will update.

[mmurooka]

@mathieu-celerier Thank you for the Pull Request for the new feature. I have a few questions.

• If you use Tasks instead of TVM as the solver (which I understand is the default), does nothing change in the behavior of the controller (including the amount of computation)?
• Even when using TVM, the behavior doesn't change unless you explicitly specify the option and add the compliance version of Posture/EndEffectorTask, right?
• I see that the compensateExternalForces option of DynamicsConstraint is not supported in Tasks. Shouldn't a warning message be output when this is specified if the solver backend is Tasks?