Move review POST endpoint to review section

[PGijsbers]

Change

Moves the reviewing endpoint to the reviewing section.
Will also move the submit & retract over, but that's better after #471 since that one already has pending changes to submissions.

How to Test

Covered by test, no new tests needed as there is no change in functionality. Can try in the front end.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.

Related Issues

[Taniya-Das]

Looks good.