Draft: 2.1: motor: Tango attr as motor

This will have to be sync with !6773 (merged)

Feature a BLISS tango motor controller from tango device attributes.

Supports the following tango attribute and functions

• pos_attr, name of the tango attribute holding the position
• state_attr, name of the tango attribute holding the state
• velocity_attr, name of the tango attribute holding the velocity
• acceleration_attr, name of the tango attribute holding the acceleration
• acceleration_time_attr, name of the tango attribute holding the acceleration (as an acceleration time)
• stop_cmd, name of the tango command to stop the motor

The code was tested at ID16A.

Todo

• Rebase on top of !6771 (merged)
• Takes care of the tango events (state/position)
• Takes care of inhibit events when there is a motion loop in one of the sessions (is_moving/move_done)