Fix ROOTService in Gaudi-Allen

The ROOTService is not used at present when calling Allen from Moore, using Gaudi-Allen algorithms. In fact, it crashes when enabling the monitoring in a line, likely since several instances of the ROOTService are created within the different instances of ProvideRuntimeOptions needed to provide different raw bank types.

This MR ensures there's only a single instance of the ROOTService and that it's filename can be configured to avoid clashes between tests.

Closes Moore#480 (closed)