Use a token to secure the connection

[StarLederer]

At the moment, any software that is running on the same network as the relay server is able to interact with the file system. This is not the worst because the server usually runs on localhost and limits the view of the file system but for additional security against random apps on localhost trying to do something with the file system we can introduce a token query parameter only known to Vite and the relay server that can be used to verify that the requests are coming from an app ran by Vite.