Create teleoperation example in Python

[adeguet1]

The goal is to replicate the existing teleoperation logic in Python so users can (more) easily adapt the logic to their own application. See also https://github.com/jhu-dvrk/sawIntuitiveResearchKit/wiki/Teleoperation. As it is, the Python code will not be able to send velocities (twist) along the setpoint_cp to the PSM. This is a good use case to justify adding servo_cpvf to CRTK.