[native] introduced flow type for reanimated layout animations

Summary:
To use Reanimated's new layout animations we need to add libdefs for the different animations. This diff just handles the SlideInDown and SlideOutDown layout animations along with all the necessary classes/types needed to support these layout animations. I will annotate inline with where the changes/types came from.

Linear Task: ENG-2165

Test Plan: All the testing for this diff came from its use in D5557. In that diff I was able to implement the layout actions using the appropriate type defs that I created in this diff, and I received no flow errors which I believe to be a good indicator that everything is correct.

Reviewers: atul, ashoat

Reviewed By: atul, ashoat

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5556