[Ambassadors] Fedora 27 - briefing page

[Gabriele Trombini]

The "Ambassadors briefing" wikipage has been created:

https://fedoraproject.org/wiki/F27_Ambassadors_briefing

That page gather links to the most important pages an Ambassador should
read for having the best knowledge for the events F27 related.

The announce page, of course, is not available until the release. I'll
update it when necessary.

Please read it before any event, in order to be updated.

Thanks.
-- 
Gabri