refactor: rename example to paper-example (#2509)

# Summary

Rename example app to match the pattern.

apps/paper-example/ios/PaperExample/AppDelegate.mm

@@ -0,0 +1,31 @@
+#import "AppDelegate.h"
+
+#import <React/RCTBundleURLProvider.h>
+
+@implementation AppDelegate
+
+- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+{
+  self.moduleName = @"PaperExample";
+  // You can add your custom initial props in the dictionary below.
+  // They will be passed down to the ViewController used by React Native.
+  self.initialProps = @{};
+
+  return [super application:application didFinishLaunchingWithOptions:launchOptions];
+}
+
+- (NSURL *)sourceURLForBridge:(RCTBridge *)bridge
+{
+  return [self bundleURL];
+}
+
+- (NSURL *)bundleURL
+{
+#if DEBUG
+  return [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index"];
+#else
+  return [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
+#endif
+}
+
+@end