Add simple function to handle symlinks (#53736)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53736

This change adds a simple function that manages symlinks. This is used through the stack of changes to avoid code repetition.

## Context
SwiftPM is very picky in how the header structure must be.
In order to preserve the import/include statements as much as possible when building from source, we can recreate the header structure in a temporary folder inside the react-native package using symlinks.

In this way, users can still modify the headers and build RNTester and HelloWorld using SwiftPM without breaking changes.

## Changelog:
[Internal] -

Reviewed By: cortinico

Differential Revision: D82202860

fbshipit-source-id: 0baa348c84f966a2e1eeb85b008f8e653bffe96c