[1403] Remove use of task_status

Rather than use task_status over the API to update how the QA task is doing
we now write directly to a table, QATask (qa_task) instead.

This commit adds a new command, init, to create the required table which is
defined in model.py

This also updates the reports to use the appropriate table
[1403] Remove all use of task_status - Basic compatibility with archival table used by ckanext-archiver.
[1403] Remove all use of task_status - Broken link report now uses new Archival table.
[1403] Remove all use of task_status - Bring model into line with Archiver. Add migration. Logic functions added for accessing QA info. Commandline update started. Broken link reports moved to archiver. Tests fixed.
[1418] Cached report refactor - Now use DataPipe to trigger QA off archiver. Minor fixes to QA task - now runs ok.
[1418] Cached report refactor - Openness Report refactored for new report framework.
[noticket] Increment version number to reflect big change to reports and model.
[1418] Cached report refactor - Added redirects to new reports.
[1418] Cached report refactor - One-liner.
[1418] Cached report refactor - Prevent exception when no archival/qa data.
[1418] Cached report refactor - Fix bug with Score Frequencies not showing first time.
Merge branch '1403-remove-task-status' of github.com:datagovuk/ckanext-qa into 1403-remove-task-status
[1418] Cached report refactor - Updated the command to use the logic layer rather than API, a la archiver.
[1418] Cached report refactor - Listed logic functions manually as find_logic_functions proved unreliable when running under celery - on second running it appeared to replace the function with the "warn" function - weird.