Add OpenID connect authentication to apiserver

Closes #16

See merge request !8

This adds two separate config flags both for the issuer and client id,
while the username claim and prefix are hardcoded. If configuration
flags are not specified, no OIDC authentication is enabled.

Enable proxy authentication to the apiserver

See merge request !6

Proxy authentication is required for the qpiserver
to properly authenticate against aggregated services, like some
webhooks

docs: makes the README shinier 

See merge request !5

Contribute "Availability to install as ansible collection"

See merge request !4