[Tails-l10n] Document portuguese translation team

Dear portuguese team,

please document your team, as suggested on
https://labs.riseup.net/code/issues/8085. The page is nearly empty:
https://tails.boum.org/contribute/how/translate/team/pt/ and we'd prefer
that it contains some information, like the other teams have:
https://tails.boum.org/contribute/how/translate/

Cheers!
u.