add constants for spl metric Scopes
make the name of the perfile-data csv file configurable
initial file-level metric handling
remove spl_variable.scope attribute as it is implicitly given through foreign keys
Merge branch 'feature/spl-statistics-model' into feature/spl-project-import

* feature/spl-statistics-model:
  remove spl_variable.scope attribute as it is implicitly given through foreign keys
handles insertion of vaiables and retrieval of metrics (get or create)
reduce loglevel