Split content module into configuration content and data content

"When you start a new project with a lot of people at the beginning already: consider having the hst-config and namespaces in a different content module. That way you both have your own hippoecm-extension.xml, no merge problems. Autoexport now support export to multiple content modules." - Bert

It seems to be one of the best practices to split content modules into configuration and data modules because it helps reduce merge problems and lead to better fine-grained content bootstrap modules.
On the other hand, we don't have to provide too fine-grained content module decomposition in the archetype; it should be good enough to provide a simple separation with two or three as a starting point for developers.