Add example httpd vhost config file

httpd.conf is only a partial configuration designed to be included in to
an existing vhost directive. This provides a (nearly) drop-in vhost
configuration for httpd.
Minor tidying of alert-tracks generation
Generate alert-tracks pid & log to default location

Deployment system should handle linking the original location to
wherever necessary on the specific platform.
Use correct site name for alert tracks log and pid

ENV[‘SITE’] can be specified for the crontab (and elsewhere) so
allow the option here too.
Ensure the log and pid directories exist

If the directories do not exist the daemon cannot start.
Create tmp/pids in capistrano shared directory

pids need to persist across deploys so that we can kill/restart running
processes on deployment
Add tmp/pids to example SHARED_DIRECTORIES config
Remove obsolete files.
Merge branch 'remove-obsolete-fcgi-files' into rails-3-develop
Merge branch 'rails-3-develop' of ssh://git.mysociety.org/data/git/public/alaveteli into rails-3-develop
fixup! 134d993 Use /srv/alaveteli instead of SITE_URL
fixup! 134d993 Remove PassengerGroup/User

Not available in Debian version of passenger
fixup! 134d993 Remove PassengerMinInstances

Not available in Debian version of passenger
Add link to Passenger performance tuning guide
fixup! 134d993 use apache2 rather than httpd for log dir

For dumb Debian convention
fixup! 134d993 Use easier to set up log dirs

Using alaveteli subdir means more setup; easier to just prefix the file name with alaveteli. Also use .log rather than _log to keep with original access.log and error.log convention.
Comment out forced redirect to HTTPS

Only need this if FORCE_SSL: true is set
Add example HTTPS vhost
Allow forced https rewrite to be configurable

Enable with:

    mkdir -p /etc/apache2/vhost.d/alaveteli
    cp /opt/alaveteli/config/httpd-force-ssl.conf-example \
      /etc/apache2/vhost.d/alaveteli/force-ssl.conf
fixup! ab1f215 Update SSL cert paths