feat: redirect /accounts/me to the correct /accounts/{id}

[kayra1]

Description

This change introduces a small change to the endpoints where users are allowed to use /me to refer to their own accounts. It also cleans up some of the auth middleware code to be a bit reusable.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that validate the behaviour of the software
• I validated that new and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

he's on break for a while and this is blocking