Resolve "[Queue-2.0] CSV Import for TAs"

What does this mr do?

Allow teachers to upload a CSV file with "netId","role" into queue to add several students, ta's etc.

Screenshots

before

after

Error gets displayed when there is something wrong with the CSV

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made.
• Tests were created to test the feature.
• I have updated the documentation accordingly.
• I adhere to the style guide. Closes #396 (closed)

Note: A redo after messing up !436 (closed)