Add Notification Triggers

[tbm0115]

Support for Notification Triggers and/or the support for Notification.showTrigger.

• https://web.dev/notification-triggers/
• https://www.chromestatus.com/feature/5133150283890688

[jensimmons]

The development of Notification Triggers API, part of Google's capabilities project, is no longer pursued.

from https://web.dev/notification-triggers/

[tbm0115]

Thanks @jensimmons . Looks like the article was updated two weeks after I posted this issue. I could see value in still adding this but showing that it is no longer supported.