Fixes#1301
- Ensures that the worker uses pagination properly
- Ensures that the worker handles failure as expected
- Moves marking the notification as read to after the worker processes it
- Increases the number of layers requested to 100
- Change get_repository_images_recursive to operate over a single docker image and storage uuid
- Move endpoints/sec to endpoints/secscan
- Change notification system to work with new Quay-sec format
Fixes#768
