Bug 1043604: Add global Apache configuration

A new file is added, all-servers.conf, which contains Apache settings
that should be used on all servers. The file is hooked up to our local
environment via Puppet and the WebOps team will ensure that it's also
used on our public servers.
Merge pull request #2774 from openjck/1043604-root-apache-config

Bug 1043604: Add global Apache configuration