Extract adaptors to lib

Firstly removed the dependency to the LiipDrupalCOnnectorModule to actaully be able to extract the adaptors to an external library.
The D7Config registry - since it uses function provided by Drupal - still has the dependency but it has been replaced by a setter/getter DI with lazy initialization.
Secondly the adaptors will be extracted to a separated github repository (find it at: https://github.com/liip/LiipRegistryAdaptor).