Upgrading edx-enterprise to 0.39.6.

https://github.com/edx/edx-enterprise/compare/0.39.5...0.39.6

ENT-555: Continue button is not appearing on registration page.

update django-debug-toolbar from 1.5 to 1.8

Fix LMS dashboard error, if HttpServerError occurs on ecommerce

LEARNER-2167

Throw error if celery task creation is not successfully completed.

Added new signal to refund on un-enrollment from LMS dashboard.

LEARNER-1801

length complexity added on password reset page

PROFILE_IMAGE_SIZES_MAP grouped with the similar settings

LEARNER-1492

ENT-581 Upgrade enterprise package to 0.39.5

[ENT-334] Add client-side registration form validation.

Input forms that need validation will have AJAX requests
performed to get validation decisions live.

All but a few important and common form fields perform
generic validation; these will need a back-end handler
in the future in order to have them validated through AJAX requests.

Information is conveyed on focus and blur for both
errors and successes.

In particular, implement a validation API for registration,
where a client makes AJAX calls to the endpoints requesting
validation decisions on each input. Responses are strings
dependent on the type of validation error; if no error,
then empty string to indicate OK.

Please enter the commit message for your changes. Lines starting

Bug fix: Reset "Notify users by email" check box to initial state.

LEARNER-2016 Removed waffle flag and added test for utm params on redirect

edx-submissions 2.0.6 upgrade

Update query counts for failing python tests

Separate Archived courses into a separate list in Studio

Update translations (autogenerated message)

Educator-986 large space in show answer view for instructors

Fixing flaky edx-proctoring acceptance tests

Django-wiki upgrades.