ansible: add xray_client role + playbook + [xray] inventory group

- New role: xray_client (deploys Xray VLESS+Reality client container)
- New playbook: xray-client.yml
- New inventory group: [xray] (emby-sascha, emby-chris)
- pfannkuchen.sh: new command 'xray'
- Prepared for migration from FRP to Xray tunnel

roles/xray_client/handlers/main.yml

@@ -0,0 +1,6 @@
+---
+- name: restart xray-client
+  community.docker.docker_container:
+    name: "{{ xray_container_name }}"
+    state: started
+    restart: true