Applied pylint-amnesty to common/djangoapps/entitlements

* pylint amnesty in course apps under openedx

* pylint amnesty in demographics, discussions and comments app

* pylint amnesty in openedx apps

Applied pylint-amnesty to util

Applied pylint-amnesty to courseware

Applied pylint-amnesty to course_api

update thresolds after IM security fixes 7

Adding toggle annotations for WIKI settings

* adding annotations for WIKI_HANDLING_ACCOUNT
* adding annotations for WIKI_ANONYMOUS
* add toggle annotations for WIKI_ENABLED
* add toggle annotations for WIKI_USE_BOOTSTRAP_SELECT_WIDGET

* add toggle annotations for FEATURES['ENABLE_DISCUSSION_SERVICE']
* added comments in cms/envs/common.py

bumping enterprise version to 3.17.20

Mergeback PR from private to public.

Incident Management Security Fixes 6

[BTR-53] [BB-3502] Misuse of urljoin in Gradebook URL from Instructor Panel

[TSD] annotations for ALWAYS_REDIRECT_HOMEPAGE_TO_DASHBOARD_FOR_AUTHENTICATED_USER

[TSD] adds annotations for COURSES_ARE_BROWSABLE feature flag

[TSD] add annotations for ENABLE_ACCOUNT_DELETION feature flag

[TSD] add annotations for ENABLE_BULK_ENROLLMENT_VIEW feature flag

[TSD] Documents maintenance banner switch and setting and updates switch

The old name was
`student.send_activation_email`.

The new name is now
`common.djangoapps.student.tasks.send_activation_email`.

We no longer user the old task name,
so we can safely stop registering it with Celery
workers, without fear of dropping any lingering
tasks under the old name.

Lower the UPPER_PYLINT_THRESHOLD to 4000