Log in with external Peertube account (#348):

* For anonymous users: new "log in using an external account" dialog, with the "remote Peertube account" options
* ConverseJS: using global vars for custom localized string (injected
  using Webpack)

server/lib/conversejs/params.ts

@@ -77,6 +77,8 @@ async function getConverseJSParams (
   } = connectionInfos
 
   return {
+    peertubeVideoOriginalUrl: roomInfos.video?.url,
+    peertubeVideoUUID: roomInfos.video?.uuid,
     staticBaseUrl,
     assetsPath: staticBaseUrl + 'conversejs/',
     isRemoteChat: !!(roomInfos.video?.remote),