Support changing javascript bundle location in runtime (#5247)

lib/ios/RNNBridgeManager.h

 
 @property (readonly, nonatomic, strong) RCTBridge *bridge;
 
+- (void)setJSCodeLocation:(NSURL *)jsCodeLocation;
+
 @end

lib/ios/RNNBridgeManager.m

 	return self;
 }
 
+- (void)setJSCodeLocation:(NSURL *)jsCodeLocation {
+	_jsCodeLocation = jsCodeLocation;
+}
+
 - (void)registerExternalComponent:(NSString *)name callback:(RNNExternalViewCreator)callback {
 	[_store registerExternalComponent:name callback:callback];
 }

lib/ios/ReactNativeNavigation.h

 
 + (UIViewController *)findViewController:(NSString *)componentId;
 
++ (void)setJSCodeLocation:(NSURL *)jsCodeLocation;
+
 + (RCTBridge *)getBridge;
 
 @end

lib/ios/ReactNativeNavigation.m

     return [RNNLayoutManager findComponentForId:componentId];
 }
 
++ (void)setJSCodeLocation:(NSURL *)jsCodeLocation {
+	[[ReactNativeNavigation sharedInstance].bridgeManager setJSCodeLocation:jsCodeLocation];
+}
+
 # pragma mark - instance
 
 + (instancetype) sharedInstance {