feat (NavBart Styling API) add Nav Bar Styling Api support
feat (loadTheme Styling API) add loadTheme api -> steroids.app.loadTheme
feat (NavigationBarButton Styling API) create NavigationBarButton with style parameters
feat (TabBar and TabBarItem Styling API) styling API for TabBar and TabBarItem
Merge branch 'pentateu-topic/styling_apis' into next