IncludeFieldsWhenDestructuringAttribute for inclusive field destructuring

Still a WIP, but below is the basic usage...

```csharp
class Program
    {
        static void Main(string[] args)
        {
            var logger = new LoggerConfiguration()
                .Destructure.UsingAttributes()
                .WriteTo.ColoredConsole()
                .CreateLogger();

            var record = new RecordWithFields {FieldA = "A"};
            logger.Information("Logging {@record}", record);
        }
    }

    [IncludeFieldsWhenDestructuring]
    class RecordWithFields
    {
        public string FieldA;
    }
```