automate das2_srv_arbiter startup at system boot

We need a way to have at least one worker automatically start at system boot.  

The most common ways to handle this are systemd unit files and systemV init scripts.   Maybe examples of each should be placed in PREFIX/etc by the install command.

Furthermore the worker program must be tested as a properly behaved daemon.  Reliance on the python-daemon package may be the way to go. 