Moves ENABLE_ENTERPRISE_INTEGRATION to settings.FEATURES,
and changes the default value to False.

This incorporates a migration that copies data
from certain models to another.

LEARNER-1523
LEARNER-1524

Enrollment attributes are now always stored, regardless of whether an enrollment is being created or updated. This will ensure that learners who purchase paid modes, without first enrolling in a non-paid mode, can request refunds if they choose to un-enroll from a course run within the refund window.

LEARNER-1282

LEARNER-394

There are a number of Django Signals that are on the modulestore's
SignalHandler class, such as SignalHandler.course_published. These
signals can trigger very expensive processes to occur, such as course
overview or block structures generation. Most of the time, the test
author doesn't care about these side-effects.

This commit does a few things:

* Converts the signals on SignalHandler to be instances of a new
  SwitchedSignal class, that allows signal sending to be disabled.

* Creates a SignalIsolationMixin helper similar in spirit to the
  CacheIsolationMixin, and adds it to the ModuleStoreIsolationMixin
  (and thus to ModuleStoreTestCase and SharedModuleStoreTestCase).

* Converts our various tests to use this new mechanism. In some cases,
  this means adjusting query counts downwards because they no longer
  have to account for publishing listener actions.

Modulestore generated signals are now muted by default during test runs.
Calls to send() them will result in no-ops. You can choose to enable
specific signals for a given subclass of ModuleStoreTestCase or
SharedModuleStoreTestCase by specifying an ENABLED_SIGNALS class
attribute, like the following example:

    from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase

    class MyPublishTestCase(ModuleStoreTestCase):
        ENABLED_SIGNALS = ['course_published', 'pre_publish']

You should take great care when disabling signals outside of a
ModuleStoreTestCase or SharedModuleStoreTestCase, since they can leak
out into other tests. Be sure to always clean up, and never disable
signals outside of testing. Because signals are essentially process
globals, it can have a lot of unpleasant side-effects if we start
mucking around with them during live requests.

Overall, this change has cut the total test execution time for
edx-platform by a bit over a third, though we still spend a lot in
pre-test setup during our test builds.

[PERF-413]

ECOM-5936

This reverts commit 21746f1e.

ECOM-4763

ECOM-4214

* mattdrayer: Add bulk checkout link to course views
* asadiqbal08: MAYN-225 replace the "Verify Now" button by the "Go to Dashboard" button in case of themed sites.
* mattdrayer: Add bulk_sku check in courseware.views

* mattdrayer: Add bulk checkout link to course views
* asadiqbal08: MAYN-225 replace the "Verify Now" button by the "Go to Dashboard" button in case of themed sites.
* mattdrayer: Add bulk_sku check in courseware.views

By default, disable all caching in tests, to preserve test independence.
In order to enable caching, inherit from CacheSetupMixin, and specify
which cache configuration is needed.

[EV-32]

The TestCase API doesn't accept arguments, so passing arguments for some
TestCase subclasses makes adding new inheritance/mixins tricky. Instead,
prefer configuration via class attributes for TestCases.

More accurately, this creates a 4th shard because the
last shard is always the default.

More accurately, this creates a 4th shard because the
last shard is always the default.

ECOM-2972

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

* Upgrade edx-submissions
* Upgrade edx-ora2
* Upgrade edx-val
* Upgrade edx-proctoring
* Update all edx-platform code that depends on DRF, including:
  - auth_exchange
  - cors_csrf
  - embargo
  - enrollment
  - util
  - commerce
  - course_structure
  - discussion_api
  - mobile_api
  - notifier_api
  - teams
  - credit
  - profile_images
  - user_api
  - lib/api (OAuth2 and pagination)

The list only includes those courses the requesting user has staff access for.

Facilitates revocation of enrollments in expired modes. XCOM-490.

Sets the Enrollment API free of the modulestore by replacing modulestore queries with calls to the CourseOverview model. Course deletion invalidates the corresponding CourseOverview. XCOM-462.

Changed enrollment api to set enrollment atributes if the course is
credit course

ECOM-1719