PROD-465

This prevents errors when the current children do not match the
selected children any more.

The Randomized Content Block XBlock only randomizes the selection of
the children blocks and has unpredictable randomization of
the order of the selected child blocks due to the usage of sets, which
are unordered, for storing the selected blocks. This becomes apparent
when all the available child blocks in a library are chosen for a
Randomized Content Block, to randomize just the order of the child
blocks and not just the selection of the blocks. The order of the
selected blocks ends up being similar for multiple learners.

This change modifies the XBlock to store the selected child blocks in
a list, instead of a set, after randomly shuffling them.

PROD-410

The `NoneType` object is not available from the `types` module in
python 3. This is a workaronud to deal with that.

Use `ascii_letters` instead which is a reasonable alternative for our
usecases.

Currently, enrollment support tool is only allowing support members
to change course enrollment only one of the two modes i.e. audit and
verified.To move a learner other than these modes,they need to ping
devops.To broaden the scope of enrollment support tool,changes have
been done so that enrollment would be changed to other modes as well.

PROD-305

* Remove full table scan of VerificationDeadline.

Before this commit, we were doing a full table scan of
student_verificationdeadline, loading the results into a giant
dict, and reading/writing that to the cache. This was fine when the
code was introduced and there were dozens of courses, but now that
we're over 12K courses, it's becoming a major performance issue for
the Student Dashboard.

This uses a subquery to the course enrollment table so that we're
only ever pulling back the deadlines to a student's enrolled courses
for any given request. It removes the cache access entirely.

Moved secondary SSO login button to the top of email and
password fields.

PROD-478

* INCR-460: Make compatible with Python 3.x and disable: import-error for urlparse

* INCR-460: Fixes for useless suppression

* INCR-449: Make compatible with Python 3.x

* INCR-449: Fixes for line long

changes made to comply with quality

changes made to comply with quality

changes made to comply with quality

Inlines all 36 discussion underscore templates

imported by lms/templates/discussion/_underscore_templates.html
to reduce file system load when displaying inline discussion blocks.

Ignored error where fix required changing the translated text string,
due to differences between underscore and HtmlUtils format strings.

on mentioned files in INCR-451
 Please enter the commit message for your changes. Lines starting

After executing python-modernize and isort, few changes
occurred in import sequence as well as unicode func is
replaced by six.text_type func.

INCR-453

After executing python-modernize and isort, few changes
occurred in import sequence as well as unicode func is
replaced by six.text_type func.

INCR-441

This is part of a multiple PR to escape
edx-platform templates to prevent xss attack.

PROD-465

Created a data migration to add system wide student support
role, also registered SystemWideRoleAssignment into Django
admin.

PROD-433

Added absolute_import
Changed unicode() with six.text_type()

Added additional logs in the certificate generation
task being executed after id verification of a learner.