fixed bug in AssetService
Properly combined UserValidator and UsersFormValidator in UsersFormViewModel
Created style to show validation errors nicely
Merge remote-tracking branch 'origin/master' into wpf

Conflicts:
	Arvato.TestProject.UsrMgmt.UI.Desktop/ViewModels/UsersFormViewModel.cs
Merge remote-tracking branch 'origin/master' into wpf

Conflicts:
	Arvato.TestProject.UsrMgmt.UI.Desktop/Views/Users/UsersFormPage.xaml