contint: reduce duplication with mediawiki::packages

The contint::packages class has a lot of duplication with
mediawiki::packages and is installed on all hosts. Slightly unclutter
the former by using the later instead.

As a side effect, php-apc is installed again, so provide a simple ini
file that disables it.

Change-Id: I09f760213e90e5802c7a1ac63341e8af9a31e2d0
Merge "contint: reduce duplication with mediawiki::packages" into production