Add system integration part

* audio/video objects will be already created within the db8 database whe they get
  successfully discovered
* by default indexing /media/internal but configurable through configuration file

Signed-off-by: Simon Busch <morphis@gravedo.de>
Correctly add/remove files when directories are deleted or moved

Signed-off-by: Simon Busch <morphis@gravedo.de>