Update to use `/var/moin` instead of `/var/www`.

In my previous deployments, I've had more success using a custom
directory instead of repurposing the traditional webroot directory.

This is more generally a FYI that I am putting together a final commit
to this repository. I need to start migrating to `moin2`.

restructured container for security, readability; re-wrote documentation

initial commit with unvendored files