Add actuators position and velocity update in SendCommand to handle case in which PyBullet simulator is run faster than the control loop

Take into account lever arm of IMU when generating IMU acceleration in simulation to mimic what we have on real robot

Adaptative spawning height of the robot in PyBullet world depending on the initial angular positions of actuators

Integration of the new blocks in the main loop to run on the real robot or in simulation + In openloop for now

PyBullet simulation is now hidden in a wrapper that mimics the interface we have when using the real robot, new classes and functions

Integration of estimator in the control loop + Small changes for PyBullet environement + Figures to test the estimator