Fix health check URL to include HTTP relative path

- Include keycloak_quarkus_http_relative_path in health_url construction
- Use rstrip('/') to handle both default '/' and custom paths like '/auth'
- Replace hardcoded 'master' realm with keycloak_quarkus_master_realm variable
- Add keycloak_quarkus_validate_certs option for SSL certificate validation
- Update documentation in meta and README

Fixes #299

roles/keycloak_quarkus/vars/main.yml

@@ -4,7 +4,7 @@ keycloak: # noqa var-naming this is an internal dict of interpolated values
   config_dir: "{{ keycloak_quarkus_config_dir }}"
   bundle: "{{ keycloak_quarkus_archive }}"
   service_name: "keycloak"
-  health_url: "{{ keycloak_quarkus_health_check_url | default(keycloak_quarkus_hostname ~ '/' ~ (keycloak_quarkus_health_check_url_path | default('realms/master/.well-known/openid-configuration'))) }}"
+  health_url: "{{ keycloak_quarkus_health_check_url }}"
   cli_path: "{{ keycloak_quarkus_home }}/bin/kcadm.sh"
   service_user: "{{ keycloak_quarkus_service_user }}"
   service_group: "{{ keycloak_quarkus_service_group }}"