WL-3190 Method for long / short labels

The logic for determining how to display a short or long label is separated
using a private method.
WL-3190 Rename existing getLongAccessLabel

This is probably a bad move because I am creating another public method
with the exact same type signuture. That said it is used once in the UI.

The benefit is that we now have a much more descriptive method name and
I've thrown in some documentation because I'm nice like that.
WL-3190 Get long access labels

As a complement to #getShortAccessLabel, introduce a method to expose the
long version of an access label.

This will be used in the 'more' context, when someone views a resource's
properties when they do not have rights to edit them.