DataTable: detects automatically selectionMode based on selection VE/value

[Rapster]

Description

Just like DataTable#lazy, it should be possible to determine selectionMode value (single, mutiple) based on selection VE or value. If a Collection, we can assume it's multiple selection, otherwise single

Describe the solution you would like

Automatic single selection (selectedProduct being a single object):

<p:dataTable var="product" value="#{dtSelectionView.products}" selection="#{dtSelectionView.selectedProduct}">

</p:dataTable>

Will enable single selection

Automatic multiple selection (selectedProducts being a collection of object):

<p:dataTable var="product" value="#{dtSelectionView.products}" selection="#{dtSelectionView.selectedProducts}">

</p:dataTable>

Will enable multiple selection