[v2] Support UIBarStyle for topBar and bottomTabs (#3519)

* Support UIBarStyle for topBar and bottomTabs

* Added to docs

docs/docs/styling.md

   backgroundImage: require('background.png'),
   rootBackgroundImage: require('rootBackground.png'),
   topBar: {
+    barStyle: 'default' | 'black',
     translucent: true,
     transparent: false,
     noBorder: false,
     },
   },
   bottomTabs: {
+    barStyle: 'default' | 'black',
     translucent: true,
     hideShadow: false
   },

lib/ios/RNNBottomTabsOptions.h

 
 @property (nonatomic, strong) NSNumber* tabColor;
 @property (nonatomic, strong) NSNumber* selectedTabColor;
+@property (nonatomic, strong) NSString* barStyle;
 @property (nonatomic, strong) NSNumber* translucent;
 @property (nonatomic, strong) NSNumber* hideShadow;
 @property (nonatomic, strong) NSNumber* backgroundColor;

lib/ios/RNNBottomTabsOptions.m

 		viewController.tabBarController.tabBar.barTintColor = nil;
 	}
 	
+	if (self.barStyle) {
+		viewController.tabBarController.tabBar.barStyle = [RCTConvert UIBarStyle:self.barStyle];
+	} else {
+		viewController.tabBarController.tabBar.barStyle = UIBarStyleDefault;
+	}
+
 	if (self.translucent) {
 		viewController.tabBarController.tabBar.translucent = [self.translucent boolValue];
 	} else {

lib/ios/RNNTopBarOptions.h

 @property (nonatomic, strong) NSNumber* visible;
 @property (nonatomic, strong) NSNumber* hideOnScroll;
 @property (nonatomic, strong) NSNumber* buttonColor;
+@property (nonatomic, strong) NSString* barStyle;
 @property (nonatomic, strong) NSNumber* translucent;
 @property (nonatomic, strong) NSNumber* transparent;
 @property (nonatomic, strong) NSNumber* drawBehind;

lib/ios/RNNTopBarOptions.m

 		disableTopBarTransparent();
 	}
 	
+	if (self.barStyle) {
+		viewController.navigationController.navigationBar.barStyle = [RCTConvert UIBarStyle:self.barStyle];
+	} else {
+		viewController.navigationController.navigationBar.barStyle = UIBarStyleDefault;
+	}
+
 	if (self.translucent) {
 		viewController.navigationController.navigationBar.translucent = [self.translucent boolValue];
 	} else {