Add gluebuddy client

The gluebuddy client is required for gluebuddy to retrieve users and groups membership without being able to change other keycloak data. The realm-management roles cannot be assigned yet via keycloak as it does not know about the roles and realm-management client.

playbooks/gluebuddy.yml

+- name: setup gluebuddy.archlinux.org
+  hosts: gluebuddy.archlinux.org
+  remote_user: root
+  roles:
+    - { role: common }
+    - { role: sshd }
+    - { role: root_ssh }
+    - { role: borg_client, tags: ["borg"] }
+    - { role: sudo }
+    - { role: fail2ban }
+    - { role: prometheus_exporters }
+    - { role: promtail }
+    - { role: gluebuddy }