(bug 54828) Configure FlaggedRevs for ptwiki (take 3)

This patch complements the existing configuration for
the FlaggedRevs extension for the Portuguese Wikipedia
by adding the 'validate' right to the 'autoreviewer',
'rollbacker', 'eliminator', 'sysop' and 'bureaucrat'
user groups.

The exact configuration has been kindly provided by
Danilo.mac; see bug for URL to its on-wiki version.

Bug: 54828
Change-Id: I09b5f816b09b2baed3394479f7382af42b74038f