JWT certificates that have been generated at initialization (development mode only) are always written to disk in PEM format, even if the configuration specified a .der extension. We could either write a complicated (and possibly error-prone) API for converting certificates to DER based on the file extension from the config, or just abandon DER support all together. I'll probably head for the latter approach since this platform is written for FreeTube and not meant to be run anywhere else, which means that designing the server to be configured in a particularily convenient manner is definitely not a priority.

Email addresses, once a user has signed up, need to be able to change. For that, the backend has to send an email to both the old and new address in order to ensure that the user is always reachable.

Right now, anything that is required in multiple places is either stored in the global.videu object (for configuration data) or the module exporting it is just imported wherever needed (e.g. the repositories).

This scheme kind of works, but making mistakes is quite easy and it gets more and more difficult to maintain as the codebase grows. Especially stuff like modifying types from external packages (express in this case) is probably a time bomb. We should migrate to a more sophisticated, object-oriented design. This not only provides better ways of abstraction, it also enables us to use TypeScript's type system to its full extent (I'm thinking of stuff like the request body from express, which has no central validation system right now and has an any type).

This is long overdue anyway, but we need to be able to send emails (obviously).

Blocks #4.