Refactor RCTUIManager

Summary:
Moved the view creation & property binding logic out of RCTUIManager into a separate RCTComponentData class - this follows the pattern used with the bridge.

I've also updated the property  binding to use pre-allocated blocks for setting the values, which is more efficient than the previous system that re-contructed the selectors each time it was called. This should improve view update performance significantly.

React/Views/RCTComponentData.h

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "RCTComponent.h"
+#import "RCTDefines.h"
+
+@class RCTShadowView;
+@class RCTViewManager;
+
+@interface RCTComponentData : NSObject
+
+@property (nonatomic, copy, readonly) NSString *name;
+@property (nonatomic, strong, readonly) RCTViewManager *manager;
+
+- (instancetype)initWithManager:(RCTViewManager *)manager NS_DESIGNATED_INITIALIZER;
+
+- (id<RCTComponent>)createViewWithTag:(NSNumber *)tag;
+- (RCTShadowView *)createShadowViewWithTag:(NSNumber *)tag;
+- (void)setProps:(NSDictionary *)props forView:(id<RCTComponent>)view;
+- (void)setProps:(NSDictionary *)props forShadowView:(RCTShadowView *)shadowView;
+
+- (NSDictionary *)viewConfig;
+
+@end