camera: add set_param() for modification of camera parameter value
camera: add set_param() for modification of camera parameter value

The semantics are similar to servo interface, set_param() will send a
parameter to camera in a nonblocking fashion. Parameter will be set some
time in the future.

Change-Id: Ic7346db5c57af0f95e59ec80c1a6dc6aff0372c3

open-rnd/ros3d-dev-controller