Add remote power switch to UTK server

[butler]

While rare, it can happen that the sever gets itself into a state where we cannot access it, particularly when mucking about with installations and upgrading the operating system etc. For these cases we currently have to hope that things go south when somebody is in the office at UT who can manually go to the console and reboot the system if necessary.

We should add a remote switch that allows us to reboot remotely.