LP1823981 Angular Permission Group Tree Admin UI

LP1823981 Angular Permission Group Tree Admin UI

Migrate the Admin => Server Admin => Permission Groups admin page to
Angular.

As an added feature, the interface now displays inherited permissions
alongside linked permissions for each group.  Inherited permissions
are read-only and act to indicate to the user when a group already has
a certain permission and therefore may not need a new one added.

Additionally, a new filter option is available in the linked permissions
interface for filtering the displayed linked permissions by code or
description.

Signed-off-by: Bill Erickson <berickxx@gmail.com>