Builds the Oak application and, when run directly, starts the recurring jobs and listens on LISTEN_HOST:PORT, having first signed the users out of other instances if they may no longer sign in there (FEDERATION.outgoing). A request goes through the error middleware, the compression of what is answered, the OG tags and CORS, then the routers, one per resource of the API (API.md lists them), and last the built frontend, which answers every path no router did.