Edx-proctoring

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* Update error interstitial to use the reset_exam_attempt flow that is used for other
onboarding attempt reset

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* Fix bug that was preventing exams from being reset
* Add exam removal endpoint to be used on the instructor dashboard in place of the
current exam attempt reset endpoint as we now have multiple attempts. This new
endpoint is only accessible to course and edX staff

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* Update the learner onboarding status panel on "submitted" state so learner knows they need to wait
* Added npm-shrinkwrap.json to pin the graceful-fs to version 4.2.2 to solve "primordials" exception during gulp test

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* Update endpoint that returns onboarding exam status to account for
users enrollment mode.

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* Add a dropdown component.
* If the "data-enable-exam-resume-proctoring-improvements" data attribute on the element of the ProctoredExamAttemptView
Backbone is true,

* use the dropdown menu component on the Instructor Dashboard Proctored Exam Attempt panel for proctored exam attempts in the error state, providing the following options:

* Resume, which transitions the exam attempt into the ready_to_resume state.
* Reset, which behaves the same as the previous reset functionality, originally exposed via the [x] link.
* change the [x] link to Reset for exam attempts in other states.

* If the "data-enable-exam-resume-proctoring-improvements" data attribute on the element of the ProctoredExamAttemptView Backbone is
false there is no change.

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* Replace Travis CI with Github Actions.
* If a course has a proctoring escalation email set, emails that are sent when an
exam attempt is verified or rejected will contain that email address rather than a
link to support.