Add the ability to send entire trajectories

[gonzalocasas]

Summary

As a compas_fab user, I want be able to send an entire trajectory to the robot so that I don't have to manually send individual waypoints/configurations that result from the planning tools.

Details

Describe the feature and the current behavior/state
Currently, it is needed to iterate over the waypoints in a trajectory and send them individually as send -usually ending with send_and_wait.

The ideal scenario should allow doing things like automatically vary speed using easing functions so use higher speeds at waypoints far away from collisions, and then slow down when approximating insertion frame.

Will this change the current API? How?
It should not be a breaking change.

Are you willing to contribute it?
Yes