TV: add Dataset to cms.db

This commit is part of the series that introduces task versioning
TV: add SubmissionResult to cms.db

This commit is part of the series that introduces task versioning
TV: add UserTestResult to cms.db

This commit is part of the series that introduces task versioning
TV: make Job versioning-aware

This commit is part of the series that introduces task versioning
TV: make get_task_type versioning-aware

This commit is part of the series that introduces task versioning
TV: make get_score_type versioning-aware

This commit is part of the series that introduces task versioning
TV: make task_score versioning-aware

This commit is part of the series that introduces task versioning
TV: add get_submission_results to cms.service

This commit is part of the series that introduces task versioning
TV: add function to get the datasets ES and SS have to judge for a task

This commit is part of the series that introduces task versioning
TV: make EvaluationService versioning-aware

This commit is part of the series that introduces task versioning
TV: make ScoringService versioning-aware

This commit is part of the series that introduces task versioning
TV: make ContestWebServer versioning-aware

This commit is part of the series that introduces task versioning
TV: add Dataset handlers to AWS

This commit is part of the series that introduces task versioning
TV: fix the Manager and Testcase handlers of AWS

This commit is part of the series that introduces task versioning
TV: update AWS to use SubmissionResults

This commit is part of the series that introduces task versioning
TV: allow to see submissions on a certain dataset on AWS

This commit is part of the series that introduces task versioning
TV: fix and improve the client interface of AWS

Correct the messages shown in the worker and queue statuses.

Add more useful links.

Show textareas for score type parameters to make them easier to edit
(until we find a way to wrap them up nicely).

This commit is part of the series that introduces task versioning
TV: add support to preview datasets and notify students of changes

This commit is part of the series that introduces task versioning
TV: make AWS notify other services when Datasets or Testcases change

In particular, notify them when a Dataset is created, updated or deleted
and when Testcases are added or removed, since this could cause a change
in the ScoreTypes used by ScoringService (either in their name, their
parameters or the public testcases).

Also, when the set of the to-autojudge Datasets of a Task changes (when
a new Dataset is activated or when the autojudge flag is toggled),
notify both EvaluationService and ScoringService so they can check if
they find new submissions or user_tests that need to be processed.

This commit is part of the series that introduces task versioning
TV: make SS re-send old submissions to RWS when active dataset changes

And, otherwise, send results only for the active dataset to RWS.

This commit is part of the series that introduces task versioning