Decouple CodePush initializing lifecycle from ReactPackage initailizing

[CHOIMINSEOK]

It seems CodePush instance could be instantiated multiple times on new architecture if you initiate ReactPackage in ReactHostHelper Function.

// Not working  
  override val reactHost: ReactHost get() = getDefaultReactHost(
    context = this,
    packageList = PackageList(this).packages.apply {
      // Packages that cannot be autolinked yet can be added manually here, for example:
      // add(MyReactNativePackage())
    },
    jsBundleFilePath = CodePush.getJSBundleFile(),
    useDevSupport = BuildConfig.DEBUG,
    isHermesEnabled = BuildConfig.IS_HERMES_ENABLED
  )

To prevent this, we guide to instantiate ReactPackage seperatly from ReactHost like this, but it's not intuitive, and different with default react-native configuration.

    val defaultPackageList by lazy { 
      PackageList(this).packages.apply {
        // Packages that cannot be autolinked yet can be added manually here, for example:
        // add(MyReactNativePackage())
      }
    }

  override val reactHost: ReactHost get() = getDefaultReactHost(
    context = this,
    packageList = defaultPackageList,
    jsBundleFilePath = CodePush.getJSBundleFile(),
    useDevSupport = BuildConfig.DEBUG,
    isHermesEnabled = BuildConfig.IS_HERMES_ENABLED
  )

Decouple CodePush initializing lifecycle from ReactPackage initailizing, so that RN configuration code doesn't affect on CodePush