Integrate codegen into the api snapshot and allow configuration (#55642)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55642

Changelog: [Internal]

Adds a configuration file for the snapshot generation, allowing to create multiple views of the API and different flavors.

It also adds option to include codegen in the snapshot generation. Codegen needs to be executed first, and the path to its output needs to be passed when running the generation.

Reviewed By: cipolleschi

Differential Revision: D92958731

fbshipit-source-id: 42780d25b2bc04f213e697cca0b6bde07d94ca59