SD-334: Define data schema

- Added support for custom implemantation of CRUD operations.
- Defined the schema for import ingest and added mock implementations.
- Changed the datalayes sent to signals, it is always app.data

SD-334
SD-322
SD-322: Store content from Ingest into the Content Archive

- Archive ingest based on celery. Behave tests and task result are not included here.
- Deleted app name initialisation.
SD-377: Investigate celery-eve integration issue

Fixed the celery-eve integration and add some small fixes
fix(celery): create separate worker script
SD-394: For behave tests change the app initialization in order to support celery related tests

- Fixed to work with behave
- Reverted manage and wsgi and changed on behave test config the flag CELERY_ALWAYS_EAGER to true

close #75
SD-322 : Store content from Ingest into the Content Archive

Fixed some merge generated issues
SD-322 :Store content from Ingest into the Content Archive

Changed CELERY_ALWAYS_EAGER to False by default