Basic APNS example

[maratal]

Closes #1318

I kept the UI as basic as possible, because the focus of this example app is on the push notifications. Lets discuss more prettier UI if needed.

[lawrence-forooghian]

@maratal not yet looked at the code, but my first observation is that we should probably also have a CI workflow that builds this example app?

[lawrence-forooghian]

@maratal can you please add some instructions (perhaps a README in the app's directory) about how to use this app? I checked out the code, ran it on the simulator, clicked "Activate", and the first thing I got was a crash: Terminating app due to uncaught exception 'Invalid key', reason: '<YOUR ABLY API KEY> should be of the form <keyName>:<keySecret>'. I could, of course, go and investigate this crash, but I wouldn't expect a user of our SDK to need to do so.

[lawrence-forooghian]

Just a very initial review for now - will review in more depth once I know how to use the app 😄

[maratal]

we should probably also have a CI workflow that builds this example app

ba5c780

[maratal]

can you please add some instructions (perhaps a README in the app's directory) about how to use this app?

db8de23

[lawrence-forooghian]

Also, might it be good to have the app's name be "Ably Push Example" instead of just "Push Example" so that developers know what it is when they see it / notifications from it on their device, and also to make it easier to search for?