This diff adds in puppet manifest for Keycloak:
- the definition of the SoftwareHeritage realm
- the definition of the swh-web client in that realm
I managed to test locally with docker by hacking on pupperware and using a docker image with
systemd support (inspired by docker-systemd) to run the puppet agent.
Everything works as expected regarding authentication and authorization in swh-web.
Nevertheless, puppet module for Keycloak needs to upgraded to its latest version (6.10).
Related to T1927