Reorg dirs: disentangle Models from mainwindow

t.knopffrequested to merge
reorg_dirs into develop

In this MR the dependency of Models on mainwindow has been resolved:

  • some basic interfaces (e.g. SaveLoadInterface) have been moved to Models
  • AppSvc has been split into ProjectManagerStore (stays in mainwindow) and MaterialModelStore (moved to Models)

Merge request reports