Fix admin verification

[yhtMinceraft1010X]

Fixes #143

Admin verification does not work because app.get(), app.post() etc are used to apply the verification as middleware even though this is not the correct way to do so.

Let's switch to app.use and decide whether to do the verification in the middleware using the req.method property.

[yhtMinceraft1010X]

LGTM - does this mean that we can manually set admins now? - can we do this via the UI or only through BE

There's no admin UI as of yet, but the admin service in the backend has routes that allow setting users to admins