Create simplified ably-cocoa example project for demonstrating push notifications capability

[maratal]

The current push-example-ios project is very complicated to setup for newcomers. It's overflowed with features and is not suitable as "go-to" sample if you just want to have a grasp understanding of how ably-cocoa handles push notifications.

The purpose of the new project is to demonstrate the basics of push notifications setup in ably-cocoa with as few lines of code (swift) as possible.

┆Issue is synchronized with this Jira Uncategorised by Unito

[maratal]

Internal discussion:
https://ably-real-time.slack.com/archives/CSQEKCE81/p1646653068625389

[ably-sync-bot]

➤ Andrey Nikishin commented:

Andrey Nikishin please have a look at this