Switch to a single config file, using a config group per service.

This has two advantages:

 - Avoids Naming Conflicts (e.g. backend-driver)
 - Allows common options to be specified once for all services (e.g. pybasedir, logdir)

Fixs bug #1096850

Change-Id: I5b02f591ccea6d1a8201b21c3cb8f92bcf6b30fa