feat: add iOS support

[Robin Genz]

Is your feature request related to a problem? Please describe:

iOS is currently not supported.

Describe the solution you'd like:

Add iOS support.

Describe alternatives you've considered:

Additional context:

https://stackoverflow.com/questions/20752254/using-mdm-to-configure-an-enterprise-app-via-nsuserdefaults

[Petar Petrov]

Hi, I noticed the README says:

The iOS implementation could not be tested yet. I appreciate any feedback.

Just wanted to provide some feedback that the plugin works on iOS. I've tested it on the Simulator as well as on iPhone and iPad devices. I got a small app published using this plugin.

Thanks a lot! 🍻

[Robin Genz]

@petarov That's awesome! Thank you for letting me know.