Direct link to a message

We need to add a way to direct link a message. Further more we may want to add the message id on the notification to add a direct link to it.

We should change the HTML template of converse a little bit to include an id to every message or if we don't want to handle it like that, we need to add some JS to use the url anchor & the data-msgid of the message.

But if we also want a "Direct link" shortcut like on rocket chat we have to modify the converse template.