Add example docker compose; fix dynamic reg

config/config.devenv.json

@@ -15,5 +15,8 @@
     "delayed_leave_event_delay_ms": 18000,
     "delayed_leave_event_restart_ms": 4000,
     "network_error_retry_ms": 100
+  },
+  "oidc_metadata": {
+    "client_name": "Element Call (dev)"
   }
 }