* rework extension service, separate file with config
* improve loading, optional entries
* simplify config and unify content actions
* load and merge multiple files
* improve plugin loading, introduce second demo
* move demo stuff to a plugin
* rework navbar to make it pluggable
* code and naming convention cleanup
* extension schema
* switch off custom navbar group by default
* hotfix for facetQueries issue
* consolidate files, final renames
