- Rename escape_json_dumps to dump_js_escaped_json
- Rename escape_js_string to js_escaped_string
- Update js_escaped_string to output empty string for None
- Introduce dump_html_escaped_json
- Move dump_js_escaped_json after the pipe as new best practice
- Introduce additional uses of helpers
- Introduce new djangolib directory and move js_utils

Allows support staff or global staff to view a list of a learner's
enrollments, and change enrollment modes. We generate a
ManualEnrollmentAudit record for these enrollment changes in order to
track updates. Additionally, enrollment changes are handled through
the enrollment API, which handles bookkeeping such as granting refunds
where appropriate.

ECOM-2825

Allows support staff or global staff to view a list of a learner's
enrollments, and change enrollment modes. We generate a
ManualEnrollmentAudit record for these enrollment changes in order to
track updates. Additionally, enrollment changes are handled through
the enrollment API, which handles bookkeeping such as granting refunds
where appropriate.

ECOM-2825

* Add new role for support staff.
* Move dashboard/support functionality into a new Django app called "support".
* Add support view for searching and regenerating certificates.
* Refactor certificates views into separate files.