🐛 need to get video start and end times working

This is waiting till service_item_model.rs is the model actually used
for ServiceList. Right now we are still using C++ so once that
switches, we can add it in service_item_model.

This way we don't add anymore C++ code that we are likely to throw away.

src/qml/presenter/Presentation.qml

@@ -130,6 +130,8 @@ FocusScope {
                     text: SlideObject.text
                     pdfIndex: SlideObject.slideIndex
                     vidLoop: SlideObject.looping
+                    vidStartTime: SlideObject.videoStartTime
+                    vidEndTime: SlideObject.videoEndTime
                     preview: true 
                 }