Add aliases for designs.apertis.org index page

Add aliases to the main website page for the index page URLs as redirected
from designs.apertis.org. We are redirecting to the main page as the
contents of designs.apertis.org is in the process of being amalgamated
into the website structure and thus not all the designs content will end
up under one topic.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>