Remove Google Groups suggestion

Hello!

The link https://groups.google.com/ in Debian FAQ opens the Google Login page suggesting that Debian implores the user to have a Google account.

We should drop the Google Group suggestion IMHO and use Debian Mailing Lists Archives search suggestion instead.

The suggested change has been merged in Debian website (www.debian.org)
webmaster-team/webwml!670 (merged)

Thanks!