feat: add implementation to support safari web push

[hortopan]

• Added support for safari web push.

https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/NotificationProgrammingGuideForWebsites/PushNotifications/PushNotifications.html

{
 "aps": {
    "alert": {
        "title": "Flight A998 Now Boarding",
        "body": "Boarding has begun for Flight A998.",
        "action": "View"
    },
 "url-args": ["arg1", "arg2"]
 }
}

[pimeys]

Cool. Is this something that also could be done with https://github.com/pimeys/rust-web-push

I will merge this if you feel it's important to have here, but I have no means to test any of the code...

[hortopan]

Cool. Is this something that also could be done with https://github.com/pimeys/rust-web-push

Safari's web push is not based on web push protocol (with web workers, etc) so it doesn't work with regular web pushes as everything needs to go through Apple's apns.

I think this could potentially be implemented as a dependency within pimeys/rust-web-push so that we have support across the board.