Rewrite ARTSerializablePath to use class

[Esemesek]

ARTSerializablePath.js is written using legacy helper from art/core/class. We should refactor it to use ES6 class syntax.

class ARTSerializablePath {
	...
}

[thymikee]

If anyone's interested, I started the work on https://github.com/react-native-community/art/tree/chore/path-as-class branch, but I'm likely not gonna continue and I'm also not convinced this is cleaner approach :D We'll need to override typings anyway, since art/core/path is untyped.