New following a different approach to static assets.

See https://www.jerriepelser.com/blog/using-auth0-with-vue-oidc-client-js/
for how to use OIDC client with the npm sources and per-compile updating
the static asset.

Also environment variables now work a bit differently.

Updated README.md accordingly

Superusers should see all shows. Ordinary users only those shows that belong to them.
Therefore we have to fetch the user data from the steering backend as well (OIDC info
alone does suffice here).

We need this info later too, when we implement user managament and profile settings.

In the ShowManager we now generate the GET URI depending on the superuser status.