Add support for other Helmet tools

[s-hiitola]

Tools such as helmet-utils' zone division tool and height data tool, or importing of non-hsl lines from GTFS data should be integrated to the UI, as their own tab. At the same time, we could separate the processing of bus stops and other changes to the network done in the begininning of each helmet-model-system run to its own, separate tool.

Requires work on helmet-utils and possibly helmet-model-system sides.

• Add the ability to access scenarios within Emme, in addition to working on exported scenarios