Add script to find the directory that contains the Xcodeproj (#53669)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53669

## Context

When configuring an app to build with SwiftPM from source, there is a sequence of operations we need to run in order to prepare the project correctly.

## Changed

Add a function that given the root of the app and the name of the xcodeproject file, can return the path to the Xcode project file

## Changelog:
[Internal] -

Reviewed By: cortinico

Differential Revision: D81778456

fbshipit-source-id: f7050bcb049d75a5b1cabf340a5b98f4736e60b3