See https://github.com/emn178/js-sha256/issues/18

Instead of fetching it from the configured keycloak server.

We had this initially, but switched to the server variant to make
sure we are always compatible with the keycloak version.

Now upstream keycloak has deprecated this strategy and in Keycloak 22
the server provided js bundle will be removed.

So switch back to the npm package.

We don't require npm to be installed

The old version is no longer maintained and doesn't support rollup v3

In case the current language changes or the current activity is re-selected in the
menu we don't want to lose the extra trailing path components.

Centralize the server config in one place, so it can easily be changed in one
file for all package demos.

This just adds it for the app-shell, for starters.

It got moved to https://gitlab.tugraz.at/dbp/web-components/tugraz-components/-/tree/main/packages/web-components

All apps have been ported to use that package instead.