Improve notifications while in app - detect content field and if empty, default to title in embed

Just as the title says. If a post is made where the content field is empty or not present, IE a bot posts only with an embed, push the notification with the title text.

Currently, it pushes a notification with just the bot's username and channel. It would be beneficial if users could see the context of the message while in app without having to click the notification, go to the channel, and see if it's something they are interested in.