APNS HTTP/2 push notification support

Apple has released APNS support through HTTP/2 in December 2015. This new support brings in a host of improvements over the old TCP socket approach. One very big advantage for users like me is we can send Push Notifications to iOS devices through APNS from a Shared hosting environment because many of shared hosting providers would deny opening up ports 2195, 2196 for their clients due to security concerns which is needed for communication with APNS from our Drupal website to establish a SSL TCP socket connection.

Enhancements can be read here:

• https://onesignal.com/blog/apple-just-released-http2-support-for-their-p...
• https://dblog.laulkar.com/http2-protocol-for-apns.html

The new Apple documentation also talks about HTTP/2 method and just mentions 2197 socket method as an alternative: https://developer.apple.com/library/ios/documentation/NetworkingInternet...

I think that HTTP/2 method is the way ahead and this change has to be implemented in the already very beautiful and useful Push Notification module. Special emphasis to this mention from Apple documentation:

The legacy binary interface required your provider server to employ the binary API described in this appendix. All developers should migrate their remote notification provider servers to the more capable and more efficient HTTP/2-based API described in APNs Provider API.

Reference about legacy method: https://developer.apple.com/library/ios/documentation/NetworkingInternet...

I believe this is not a duplicate request, I tried to search in open issues and did not find any. In case this is a duplicate request kindly merge with the original (if any).