Feature Request: Decouple/Split Qt Gui from core functionality

[drbenmorgan]

It would be useful to have the Qt GUI for the variant browser as a separate Widget library and/or Application and decoupled from the main datatools::kernel and datatools::variant_service. I'm not sure it's really the job of the kernel or a service to start/control the GUI, plus it links the whole of libBayeux to Qt, which is quite a heavy dependency.

Splitting into a separate repository like mctools/Geant4 in #31 would be one option (and the cleanest). Another would be to just have it as an additional library/application within Bayeux.

The use case addressed is to help in the production of lightweight Docker images of Bayeux for SuperNEMO production/cluster/cloud jobs.

[fmauger]

At least there is a BAYEUX_WITH_QT_GUI option that can be OFF (default) and allows
a Bayeux build/install without Qt.

The Qt interface emanating from the Bayeux's kernel should be removed in the future
as now we use the specific variant service in the "user" scope, typically from the "main" function.
I agree the former design was bad.

This change is not schedule today but in the todo list.

I let the ticket open.