chore: remove the xcodeproj from the library (#411)

## 📜 Description

Removed `*.xcodeproj` and all associated files.

## 💡 Motivation and Context

It seems like this file is not needed anymore as all linking is done via
cocoapods. So in this PR I'm removing it because:
- it should reduce npm package on ~19kb;
- we will not need to synchronize it with fs anymore;
- it's not used file.

Similar changes were made in
callstack/react-native-builder-bob#470

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## 📢 Changelog

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declarations; -->
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### iOS

- removed `xcodeproj` associated files;

## 🤔 How Has This Been Tested?

Tested on CI.

## 📝 Checklist

- [x] CI successfully passed
- [x] I added new mocks and corresponding unit-tests if library API was
changed