Revert boto3 upgrade

The boto3 upgrade seems to have broken in prod

EDUCATOR-1183, EDUCATOR-1203

Fix empty file description in ORA response - EDUCATOR-1054

Upgrade edx-submissions, django-model-utils

Finalize 2.0.1 release

Deprecates Workflow.uuid, to prevent the issues seen in edx-submissions
(EDUCATOR-1090). Also fixes acceptance tests, and resets the
edx-submissions version to the latest.

2.0.0 release

Also restores conf/locale, which is needed for the i18n update scripts

Tox, for parallel test goodness

Code changes needed to work with the upgraded dependencies from the
previous commit.

Contains installation and testing changes for the django 1.11 upgrade
preparedness initiative. Splits tests out into seperate shards on travis.

This work was done in the context of a larger PR, I'd be shocked if
this commit can be successfully reverted by itself. If you're trying
to restore AI grading though, it's a good place to start.

edx-submissions 2.0.6

Bump version of edx-submissions and package version.

1.4.7, patch release for edx-submissions

Rc/1.4.6

Adds django storage backend for ORA2 file uploads.

Allow LaTeX previewing for multiple prompts

Update submissions and DRF versions.

Rc/1.4.4