The previous configuration was copied over from helium.n39.eu for
prosody v0.9 and did only work more or less by accident. The new
configuration was done based on the upstream example configuration.
Some modules we used for 0.9 were replaced, some are not necessary
anymore, some modules are new for 0.11. The list was reviewed carefully
on a test host, and proved to work for several months there.
The VirtualHost 'localhost' is kept, but moved from a separate
configuration file to the main configuration, because it's only one line
and it's part of the example config anyways.
