Since *file0.pyrocufflink.blue* now hosts a couple of VirtualHosts,
accessing its HTTP server by the *files.pyrocufflink.blue* alias no
longer works, as Apache routes unknown hostnames to the first
VirtualHost, rather than the global configuration. To resolve this, we
must set `ServerName` to the alias.
This commit sets the `apache_userdir` variable, which enables the
per-user directories feature. This allows users to serve content via
HTTP by placing it in the `public_html` directory within their home
directories.
Although Apache is already installed on the file server in order to
serve the Aria2 web UI, it is not explicitly included in the
`fileserver.yml` playbook.
Dustin