Support negation, that is, not, in propositions

[simon-wacker]

I tried to do so with https://github.com/ise621/database/blob/develop/backend/src/GraphQl/DataX/DataFilterTypeBase.cs#L33-L56 but failed. With this approach I get the following runtime error

System.NullReferenceException: Object reference not set to an instance of an object.
   at HotChocolate.Data.Filters.AndField.OnCompleteField(ITypeCompletionContext context, ITypeSystemMember declaringMember, InputFieldDefinition definition)
   at HotChocolate.Types.FieldBase`1.CompleteField(ITypeCompletionContext context, ITypeSystemMember declaringMember)
   at HotChocolate.Types.FieldBase`1.HotChocolate.Types.Helpers.IFieldCompletion.CompleteField(ITypeCompletionContext context, ITypeSystemMember declaringMember)
   at HotChocolate.Internal.FieldInitHelper.CompleteFieldsInternal[TField](ITypeCompletionContext context, ITypeSystemMember declaringMember, TField[] fields)
   at HotChocolate.Internal.FieldInitHelper.CompleteFields[TField](ITypeCompletionContext context, ITypeSystemMember declaringMember, TField[] fields)
   at Database.GraphQl.DataX.DataFilterTypeBase`1.OnCompleteFields(ITypeCompletionContext context, InputObjectTypeDefinition definition) in /home/me/app/src/GraphQl/DataX/DataFilterTypeBase.cs:line 55

Ask the developers of HotChocolate to support not in addition to and and or!