Devices endpoints should not make RPC to actuator, since it no longer exists.

[davidraker]

The devices endpoints of the RESTful API make RPC calls to a hardcoded VIP Identity of "platform.actuator". Being that the actuator agent functionality has been rolled into the driver as of VOLTTRON 11, this will no longer work.

It should also be possible to override the default VIP identity of the driver, rather than hard-coding it as the acuator was before.

[drq]

@davidraker Did you have chance to fix this issue? it looks like none of the device related services is working.