Add methods and classes for Places (New) API in flutter_google_places_sdk_platform_interface

[flikkr]

Description

Add classes and methods introduced in Google Places (New) API. I have some changes to add to Android library once this is merged. Tracked by #77.

[matanshukry]

hey @flikkr , thanks for the PR!
There was a discussion not too long ago: #65
The reason I'm not so sure about moving to the new api is that least comment.

If you can comment on that with some sources from the documentation that would be great - otherwise I would want to do more research before deciding to move.

Regardless:

1. I've added a couple of review, take a look when you can
2. If you can also create a PR on how you use it - that would be great. That 2nd pr doesn't have to be perfect nor even build, but it's hard to comment on this without knowing how it will even be used.

[flikkr]

Hi @matanshukry, thanks for taking the time to look into this! I've created a sample PR #91 to show how I integrate the full feature in my project.

Regarding the concern on moving to the new API, there should not be any breaking changes as the new API can only be used once it is enabled via the Google Cloud console and initialised in app by calling Places.initializeWithNewPlacesApiEnabled. The old API can still be used by calling Places.initialize. (see migration guide)

[matanshukry]

@flikkr again sorry for the long delays;
Anyway let's just create a separate enum for the new api 🙏 , and we can merge this after

[matanshukry]

@flikkr I fixed the tests and workflow in master, after resolving conflicts it's now missing the return null statement.
Let's fix it and make sure the tests passes, and merge this

[flikkr]

Hi @matanshukry I fixed the failing test, please help to run the workflow