By default, it will build with the dev-setup where authenticated
user will be faked since there is no login page on the local dev
setup. In order to compile it with oidc, disable default features
and enable the oidc feature.
Context should contain information which is required to get
the information if the service call is authenticated. Context
could be the username for example. But services call other
services internally and for this, authentication must not be
checked. In this case, they can now pass Authentication::Full
which always successfully authenticates.
This allows us to use a service implementation which
returns a dummy user during development and the actual authenticated
user during production. It also simplifies tests.
