stats.wm.org - use apache::site

use the newer apache::site method rather than a file
resource and have proper symlinks again

otherwise it's currently:

root@stat1001:/etc/apache2/sites-enabled# file stats.wikimedia.org
stats.wikimedia.org: ASCII text, with very long lines

root@stat1001:/etc/apache2/sites-available# file stats.wikimedia.org
stats.wikimedia.org: ERROR: cannot open `stats.wikimedia.org'
(No such file or directory)

due to refactoring

also, use $site_name and make it more generic instead of
including the hardcoded sitename

PS4: also replace ports config with apache::conf

Change-Id: I371d9bba67b297091f6d8321d729394f348f57b4