EntryConvert: ReadOnly property can be edited

[dbeuchler]

Describe the bug
I am having a property within an Resource and this propery should be readable only (in ui, entryconvert).

[EntrySerialize]
public StateClassification RemoteDriverState { get; }

The UI provides me an editable combo box for this property.

Original ticket: PHOENIXCONTACT/MORYX-Framework#85