This method inserts an instance of "StartPageViewModel" into the "startPageItemsControl", results of which displays the Start Page on "DynamoView" through the list item's data template. This method also ensures that there is at most one item in the "startPageItemsControl". Only when this method is invoked the cost of initializing the start page is incurred, when user opts to not display start page at start up, then this method will not be called (therefore incurring no cost).