New Feature: adding disabledSimultaneousGesture flag to manage simultaneous gesture recognition (#1777)

docs/styling-the-navigator.md

   statusBarHidden: false, // make the status bar hidden regardless of nav bar state
   
   disabledBackGesture: false, // default: false. Disable the back gesture (swipe gesture) in order to pop the top screen. 
+  disabledSimultaneousGesture: true, // default: true. Disable simultaneous gesture recognition.
   screenBackgroundImageName: '<name of image in Images.xcassets>', // Optional. default screen background image.
   rootBackgroundImageName: '<name of image in Images.xcassets>', // Static while you transition between screens. Works best with screenBackgroundColor: 'transparent'
 

ios/RCCNavigationController.m

         [mergedStyle removeObjectForKey:@"autoAdjustScrollViewInsets"];
         [mergedStyle removeObjectForKey:@"statusBarTextColorSchemeSingleScreen"];
         [mergedStyle removeObjectForKey:@"disabledBackGesture"];
+        [mergedStyle removeObjectForKey:@"disabledSimultaneousGesture"];
         [mergedStyle removeObjectForKey:@"navBarCustomView"];
         [mergedStyle removeObjectForKey:@"navBarComponentAlignment"];
         

ios/RCCViewController.m

   return !disabledBackGestureBool;
 }
 
+-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
+  NSNumber *disabledSimultaneousGesture = self.navigatorStyle[@"disabledSimultaneousGesture"];
+  BOOL disabledSimultaneousGestureBool = disabledSimultaneousGesture ? [disabledSimultaneousGesture boolValue] : YES; // make default value of disabledSimultaneousGesture is true
+  return !disabledSimultaneousGestureBool;
+}
 
 @end