Create run-test.sh and update readme to exemplify running on iOS devices

[ralupopa]

Please add example for setup to run tests on iOS

In https://alttester.com/docs/sdk/2.0.2/pages/alttester-with-appium.html#why-use-appium-together-with-alttester-unity-sdk there is mention about:
For iOS, you first need to export IOS_UDID=<your-device-udid> then run the script run-tests_ios.sh

Or you could link in documentation example from https://github.com/alttester/EXAMPLES-CSharp-iOS-AltTrahCat/blob/master/ios_tests.sh