The accessibility of the field should not be public for keys/values from Isolated Storage

[Arthurvdv]

Inspired by the issue #578 by @pri-kise, I think a rule can be helpful to harding the security of fields used with Isolated Storage.

table 50100 MyTable
{
    fields
    {
        field(1; "My Secret"; Guid)
        {
            Access = Public; // Raise an diagnostic that the field should not be public
        }
    }

    internal procedure GetSecret() Secret: SecretText
    begin
        IsolatedStorage.Get(Rec."My Secret", DataScope::Module, Secret);
    end;
}

When a field is used to retrieve keys/values from the Isolated Storage, the field should not be public accessible.

The setting DataScope::Module already provides security hardening for retrieving the keys/values from the Isolated Storage.