[#77] Entities: Add AreaComContract to group area commitments together

Elwig/ViewModels/MemberAdminViewModel.cs

@@ -11,7 +11,6 @@ namespace Elwig.ViewModels {
     public partial class MemberAdminViewModel : ObservableObject {
 
         public int? TransferPredecessorAreaComs = null;
-        public bool MaintainAreaComYearFrom = false;
         public int? CancelAreaComs = null;
 
         public ObservableCollection<KeyValuePair<string, string>> PhoneNrTypes { get; set; } = new(Utils.PhoneNrTypes);