Install OneSingal to send web notification

[calpa]

Is your feature request related to a problem? Please describe.
OneSignal provides a simple interface to push notifications and email, letting content creators focus on quality user engagement instead of complex implementation.

Describe the solution you'd like
Install it.

Describe alternatives you've considered
Build a web push notification system

[calpa]

I am doing this.

[rrvoigt]

I also have a problem seeing our onesignal notifications in Brave.
They work normally in chrome, firefox.
https://onesignal.com