VectorXZUtils and more Vector2 utilities.

[legopitstop]

• Added more utilities to Vector2Utils
• Added VectorXZUtils with the same methods as Vector2Utils.
• Added tests for VectorXZUtils and new methods for Vector2Utils.
• Core helper tests are now split up into 3 main groups (Vector3 operations, Vector2 operations, and Vectorxz operations) for organization.

[rlandav]

Thanks for your contributions! My only ask is that we want to make sure we have a parallel Vector2Builder method for each new method added (and a corresponding VectorXZBuilder now that you've added those functions too). Thanks!

[legopitstop]

Added utilities to Vector2Builder and added VectorXZBuilder

[rlandav]

Changes to the vector wrapper look good. Can you revert the lock file changes and the gameplay-utilities changes? You might have other changes locally that are getting merged in here. Once removed, I can merge this for you.

[legopitstop]

Reverted package-lock.json and the gameplay-utilities.api.md changes.