Clean up upload UI

[PWardell86]

Medium priority.

This should be paired with the backend ticket (still have to link it).

Basically, the backend upload is async so we need some way to indicate whether the upload has completed/ failed to the person who uploaded the questions.

I was thinking websockets + a progress bar? Might be too much information. Maybe just just websocket and when the parsing is finished we display a message.

If the user reloads/ leaves the page during parsing we probably don't care. Just let the websocket die.