Fix save state

[sylvihuynh]

• Fixed the state of the score on each student answer. Now, the assessment page holds the score for all the answers.
• Save assessments on finish. When the marker finishes the assessment and clicks on the finish button, the marker is sent to the approval page and all the assessments are saved to localstorage. This saving mechanic is currently in progress, and for now it saves to the same key 0. The assessments in the localstorage is also replaced for each saving meaning that only the newest version is saved.
• Add prettier extension to all files

[amalieeh]

I tried looking at having single quotes in imports, but I could find a nice solution either :/ (with prettier)