Add RSS feed

[pronskiy]

This adds an ability to subscribe to events with RSS.
The feed is available at /feed URL path.
Events are sorted by create date not by start date, so that subscriber knows when new events are added.

[ericlbarnes]

Thanks for this! I hadn't considered adding an RSS feed because I wasn't sure if anyone still used it, but happy to hear there are people that are still using it.

I'd much prefer this if you simplified and removed the 3rd party package requirement. Ideally, you should be able to grab all the future events and just loop them in an RSS blade view. Sort of how I'm grabbing all the events for the JSON API:

https://github.com/laravelnews/laravelevents/blob/master/app/Http/Controllers/HomeController.php#L14-L17

[pronskiy]

Eric, thanks for the review. I'll remove the dependency and update the PR soon.