Add (native) Traefik support to synapse-admin

Previously, it had to go through matrix-nginx-proxy.
It's exposed to Traefik directly via container labels now.

roles/custom/matrix-synapse-admin/tasks/setup_uninstall.yml

@@ -18,3 +18,8 @@
       ansible.builtin.file:
         path: "{{ devture_systemd_docker_base_systemd_path }}/matrix-synapse-admin.service"
         state: absent
+
+    - name: Ensure matrix-synapse-admin directory doesn't exist
+      ansible.builtin.file:
+        path: "{{ matrix_synapse_admin_base_path }}"
+        state: absent