Prefix to the prefix

[CJ-Wright]

It might be good to put a prefix to the prefix onto all our servers. The pre-prefix could be written into config files at the beamlines and be endstation specific. This way no matter how many (or few) message buses we have we can run all the data analysis as needed. Additionally this would allow users to run post-facto analysis while users are doing inline analysis (since we can have the post-facto analysis take on a different prefix).