Extend the `WindowedList` to accept a renderer to support ARIA attributes

[afshin]

We should follow the renderer pattern we have in other content-creating widgets to extend the WindowedList class to allow for the instantiator to create correct markup and attributes.

cc: @gabalafou, @fcollonval, @tonyfast

Problem

The windowed list class is not specific to only notebooks, so we can't hard-code appropriate ARIA attributes into its DOM output.

Proposed Solution

Allow a renderer to be passed in at instantiation time.

Additional context

This is a sub-task of: #14768

[gabalafou]

Some code hints from Frédéric