📙 Update docs for ParseFacebookUtils using the new Activity Result APIs for onActivityResult calls

[azlekov]

Link to section:
https://docs.parseplatform.org/android/guide/#facebook-users

What is the issue?

Using of onActivityResult method of Fragment is now deprecated which can lead to confusion and questions or reported issues on the Parse Android SDK repo.

Can you propose a solution?

In addition of the current documentation add steps how to use the ParseFacebookUtils with the new Activity Result APIs a good old-way, new-way guide can be found in this StackOverflow topic