The new install screen will now show up for iOS versions from 15.0 onwards

Changed deployment target to reflect recent changes to the app

Without ScribeColors before it, just the key would cause an "Ambiguous use of '.key'" error in the compiler. I assume this was something changed for iOS 14 or 15, the code won't compile unless you specify the used colour library.

- iOS deployment target in project.pbxproj is now correctly set for all keyboards.
- Simplified code that doesn't require the #available tag for the new target

titleEdgeInsets seems to have been deprecated since 15.0, Xcode said it would be ignored in it so it seemed like a good idea to remove it.