is_resumable added and used on UI to allow resume on error exam attempts reviewed

[feat]: MST-817 allow exam attempt to be resumable through the new is_resumable model field. Expose the is_resumable boolean field from the ProctoredExamStudentAttempt table through the proctoring API and restful web API. Update the UI to use the is_resumable property on the attempt model instead of 'error' status. This change will allow exams to be resumable even if the attempt is in reviewed status like 'verified' or 'rejected'

3.9.0 Sequence Exam Data Endpoint

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#390---2021-05-07

3.8.9: Update confusing language on proctoring info panel

Merge pull request #840 from edx/alangsto/update_language_for_verifie…

…d_onboarding

fix: Remove confusing language on proctoring info panel

3.8.8: Exam Error Logging

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#388---2021-04-23

Add pyjwt as a Dependency and Add a Version Constraint

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#387---2021-04-16

Add RST Validation and Update Python Requirements

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#386---2021-04-13

Display Useful Status in InstructorDashboard StudentOnboardingPanel for "onboarding reset" Attempt Status

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#385---2021-04-07

3.8.4: Pass username into proctoring info panel

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#384---2021-04-05

3.8.3: Use due dates on onboarding exams for onboarding status panel visibility

Show onboarding panel before the onboarding exam is visible, AND after the onboarding exam is passed due. This means, we will always use exam due date or course_end date (if they are specified) to pass into learningSequence processor

3.8.2: Add ping interval to Django settings

https://github.com/edx/edx-proctoring/blob/master/CHANGELOG.rst#382---2021-04-02