fix: Convert NewOrderSingle to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Convert OrderCancelRequest to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Reformat message traits

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>