Rudimentary control of the Cheetah pipeline via PSS.CTRL

Skeleton implementation of the CTRL device as described by PSS DDD.

CTRL is part of the SKA LMC infrastructure and it acts as a bridge between the PSS.LMC core devices (Controller, previously Master, and Subarray) and the sidecar style Cheetah pipeline control container. It can run and stop the pipeline, and it forward the configuration, either as command line switches or as XML file. It is also capable of collect the syslog style output of Cheetah and parse it.