[Doing-228] Removed UMAnalytics from xFaceLib. Instead, implement it as a standalone extension
Clean up config.xml, removed unused preferene 'SplashScreenDelayDuration'

SplashScreenDelay is not used by Cordova iOS, if xFace iOS still
needs this preference, define it’s value in plugin.xml
[Done-231] Since XAppUpdater is not used at present, removed XAppUpdater and related preferences from xFaceLib