Bug 27495: Added Accessibility advocate role in team page

Bug 27495: Added Accessibility advocate role in team page

Test Plan
1. Click on 'About Koha' from the home page
2.Check on the  Koha Team page that the role Accessibility advocate is
listed under the Koha release teams and that the name of the person with
the role  appears.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>