Update keycloak to the latest version

From version 17.0 and on, the keycloak distribution uses Quarkus instead of Wildfly. We should migrate to the latest version ASAP...

Relevant links:

• https://www.keycloak.org/docs/latest/upgrading/index.html#migration-changes

Test and deploy versions:

• 20.x
• 21.x
• 22.x