Renders as markup the specified list item value into the specified element, usually as a text node.
Default implementation delegates to the default {@link org.itsnat.core.domutil.ElementRenderer}.
Default implementation ignores isSelected and hasFocus (current implementation of ItsNat lists does not handle focus on list items, ever is false).
@param list the list component, may be used to provide contextual information. Default implementation ignores it.
@param index the list item index.
@param value the value to render.
@param isSelected true if the list item is selected.
@param hasFocus true if the list item has the focus.
@param cellContentElem the list item content element to render the value into. Is a hint, if provided should be obtained by calling
list.getItsNatListUI().getContentElementAt(index).
@param isNew true if this is the first time the markup is rendered. Default implementation ignores this parameter.