[1403] Removes use of task_status

Now stores relevant information in the ArchiveTask model (archive_task table)
which removes the need for updating the task_status API
[1403] a default config file
[1403] Remove all use of task_status - Archiver table now used exclusively. Works from command-line and notifications.
[1403] Remove all use of task_status - Fix bug counting failures.
[1418] Cached report refactor - Moved broken link reports here from ckanext-dgu. Register reports using new 1418 infrastructure.
[1403] Remove all use of task_status - Reorder methods in tasks.py for ease of understanding.
[1403] Remove all use of task_status - Add model method for per-package access.
[1418] Cached report refactor - Add DataPipe concept for ckanext-qa to trigger off ckanext-archiver - added interface for it and connected up to ckanext-qa. Stop archiving deleted resources... Merged broken links reports into one registered report - an index of orgs and per org.
[1418] Cached report refactor - Add total for broken links.
[1418] Cached report refactor - 404 instead of exception for bad org in report.
[1418] Cached report refactor - Move imports to allow celery_app to init ok when running "paster archiver init".
[1418] Cached report refactor - Slow down loading resources onto queue to avoid overload errors.
[1418] Cached report refactor - Slow down loading resources onto queue to avoid overload errors.