Added DossierController, still subjected to be changed.
Changed seed method implementation.
Added method for registering / configuration of the serializers.
Fixed problem with not loading dossier.
Added NotFound return types when the user or dossier could not be found.
Removed Post, Put and Delete action methods from the DossierController (WebAPI).
Merge branch 'feature/api-dossier' into develop, containing the basic DossierController.
Supports only the Get request, and is still subject to change.