Config definitions should belong to the config model

[bratseth]

Today config definitions are resolved in the config server. This makes it hard to make braking config definition changes in major versions in a clean way.

The config definitions should be part of the config model instead.

[gjoranv]

Work note: Internal config defs should not be handled specially. That is a remains from the time before the configserver was moved to the container. If they were loaded from the model bundles, the version problem would disappear by itself.