Add aliases for running cxx-api scripts (#56145)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/56145

Add npm aliases for running python cxx-api snapshot generation script (build and validate):

```sh
python -m scripts.cxx-api.parser // cxx-api-build
python -m scripts.cxx-api.parser --check // cxx-api-validate
```

and also a js1 wrapper for buck equivalent.

Changelog:
[Internal]

Reviewed By: cortinico

Differential Revision: D97132752

fbshipit-source-id: e35d6d037ba3dad2a6b3294d0de9f5041847b33a