[TIMOB-18909] Expose build and named version via Ti.App

Currently, we set Ti.App.version to the version-tag of the tiapp.xml file: https://github.com/appcelerator/titanium_mobile/blob/35c0034605a800f5a6241d602a58d744222b2e1a/iphone/cli/commands/_build.js#L2816 For Android you can already set the versionName and versionCode directly and once TIMOB-17993 is resolved so can you for iOS's CFBundleShortVersionString and CFBundleVersion. If you set these, then Ti.App.version may not be the actual release version, affecting our own analytics - which uses this value - as well. Suggestions: * Let android:versionName and CFBundleShortVersionString override <version> Ti.App.version * Let android:versionCode and CFBundleVersion override <build> for Ti.App.build once TIMOB-19173 is resolved