Only display debug toolbar on non-ajax requests.

The verified seat upgrade deadline for self-paced course runs is now
dependent on when the learner was first able to access the content--the
latest of enrollment date and course run start date.

Update UBCPI to 0.6.4

Educator-699 Modify deleted group warning on the unit/container page

Collect translation strings from the openedx folder

Implement theme admin UI to support previewing

LEARNER-2112

LEARNER-2017

EDUCATOR-1001 Fix language for visibility editor and validation to include units

Educator-9 Removed comment about changing warning to exception

Upgrade edx-enterprise package to 0.39.1.

PLAT-1590 Fixes for Docker Devstack e2e tests

EDUCATOR-842: adds in management command for verified_tracks

bump edx-sga XBlock to v0.6.4

Re-add to BlockStructure cache on miss.

This model will soon be deleted.

LEARNER-2042

EDUCATOR-842: adds in management command to swap a course's xblocks from verified track cohorts to enrollment tracks

BlockStructures are stored in S3, but they're cached in memcached. Prior
to this commit, they were only written to memcached when first created.
This commit adds a write to repopulate the cache entry every time there
is a cache miss. Hopefully, this will help reduce the miss rate we're
seeing.

Make HTTP 500 error pages site-aware

Catch exception with duplicate username/email

Fixing whitelabel messaging issue.

WL-1147

Switching edx.org and openedx images.

Handle tab hiding at a different level.

Template were using global TECH_SUPPORT_EMAIL for error pages. This
changes them to use the site email if there is one.

Return no libraries if org not specified

Upgrade django-oauth-toolkit to 0.12.0

[ENT-491] Check for Enterprise-linked TPA pipeline when asked for Enterprise on request

Due to a bug in org=None vs org='', all libraries were being returned
from the "optimization" in #15292. This fix returns no libraries on the
default '' value.