waves notifcations

[stefan_h]

when signed up to notifications, there's no preview on the swell on the email, only the weather.

[pavelneuman]

@stefan_h Notifications will get total overhaul, see this thread: https://community.windy.com/topic/9760/would-you-like-to-receive-windy-alerts-as-push-notifications-to-your-mobile-device/