SOL-1390: Cert Exceptions: View and Edit Exception list

[saleem-latif]

Hi @ziafazal , @asadiqbal08 ,

Kindly review this PR, it contains changes for SOL-1390,

Description of SOL-1390:
Background
There is currently no way to view the exception list or remove a user from exception list, it would be good to have the ability to remove user from exception list.
Acceptance Criteria

1. In the Certificate Exception section of the Certificates tab on the Instructor Dashboard: Add a table view of all exceptions added to the course:
   Username, Email address, Date Added, Notes
2. Add a "Remove from List" button that allows the PM user to remove a user from the exceptions list.
   If the system has already generated a certificate for a user that we'd like to remove from the list, invalidate that certificate

DESIGN NOTES:
Add the list of users who have been granted exceptions BELOW the Generate Exception Certificate button

cc; @mattdrayer

[ziafazal]

Is this CertificateWhitelistFactory call required in this test scenario?

[saleem-latif]

@ziafazal , @asadiqbal08 I have incorporated your feedback, kindly take a look.

[ziafazal]

Name of this method does not reflect the operations it is doing. May be we can rename it to parse_and_get_user or split this in to two methods one which parses user data and other one fetch user object.

[saleem-latif]

@ziafazal , @asadiqbal08 I have incorporated the feedback, kindly take a look. After the review, I will rebase the branch with master resolve conflicts.

[ziafazal]

@saleem-latif LGTM 👍

[asadiqbal08]

@saleem-latif We should check for student enrollment in course as well, I think this code will push the user in white-list without checking his/her enrollment in the course.

[saleem-latif]

@asadiqbal08 This has been incorporated with SOL-1389.

[asadiqbal08]

@saleem-latif beside the above comment, These changes are looking good to me. 👍
kindly resolve the conflicts for this PR.