Update keycloak to v19.0.3 + configure keycloak via init-job instead of realm_import + correct user endpoints in kaapana-backend
- Keycloak is updated to version 19.0.3 using the corresponding docker images from here https://quay.io/repository/keycloak/keycloak?tab=tags
- Keycloak doesn't import a realm anymore
- The kaapana realm, the kaapana client and a default user + group are created via an init job
- The user endpoints in the kaapana-backend are working now.
- The way how the kaapana login theme is integrated has changed
- The default keycloak theme is copied from the keycloak github repo.
- Note: This theme contains the MIT License
- The documentation was updated to the new keycloak version