Remove extraneous direction param at end of move commands

[margyle]

Direction is now handled by positive or negative values for steps and angles. The move command formatting still requires a direction parameter as the last value. This is a holdover from an earlier implementation.

Remove it and do a full regression test for all move functionality.

[margyle]

Example param in the JSON being sent to the mech control python service:

Note, this refactor will touch both the mech-control service and the arduino code.