On iOS, if the app is closed the startup options are only passed as the
`launchOptions` dictionary of `applicationDidFinishLaunching`. Thus add a helper
method to be called from there by embedding applications so we can copy that
dictionary.

1. Aligns the project structure of Jitsi Meet SDK for iOS with that for
   Android for better comprehension.

2. The command `react-native run-ios` uses the last Xcode project or
   workspace in the list of these sorted in alphabetical order. Which
   limits our freedom in naming. Thus having only an Xcode project in
   the root directory of the iOS project structure gives us back the
   freedom in naming.

3. Allows the Podspec to work for the app project in addition to the sdk
   project because we need Crashlytics in the app which is integrated
   via Cocoapods as well.

4. Further removes references to JitsiKit in the source code for the
   sake of consistent naming.