Trapezoidal motion profiles

[hello-robot-shehab]

Stretch Body's position control uses a trapezoidal motion profile to track position goals. The API allows the user to optionally specify the velocity and acceleration that the profile should use:

1. https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/base.py#L141
2. https://github.com/hello-robot/stretch_body/blob/master/body/stretch_body/prismatic_joint.py#L347

It would benefit sim-to-real transfer to use the same motion profile interface used by the real robot. Additionally, to provide similar control API as Stretch Body.