feat(native-storage): add initWithSuiteName

[tatham]

Required if you want to provide access to storage shared between apps in an app group in iOS.
Relevant section of the documentation for the plugin:
https://github.com/TheCocoaProject/cordova-plugin-nativestorage#usage

[danielsogl]

Please add an callback interface of set the return type to Promsie<void> if the callback is empty

[tatham]

I don't understand, do you mean that the return type should be changed to Promise<void> or that it needs some logic to check for empty? I've found that the underlying plugin code doesn't recognise an undefined variable (or an empty string) as a null parameter, and so it never returns an error message.

[danielsogl]

If your promise callback contains Data you should add an interface describing the data like Promise<MyCallbackInterface>.

[tatham]

OK, I was following the style of the other methods, which return Promise<any>, but I will change this to Promise<void>, as the plugin implementation never returns the error message.
I have two other questions:

• I've realised that I can add platforms: ['iOS'] to the decorator, as this is iOS only. Should I do that?
• Do I need to raise a separate PR if I want to add the same changes to the v4 branch?

[danielsogl]

Yes, you should add the platform. Ionic Native 4 is not supported anymore so you don't have to create another PR.

[tatham]

Great, thanks. Requested changes have been made.