Adding sample app for initialising passport

[BounceyBytes]

Summary

Creating a very simple sample app that initialises passport. This will be used to generate how to guides in our docs that are always up-to-date bc we will later integrate this sample app with the ci/cd pipeline for the unity sdk.

Customer Impact

This will help create better docs.

Added

New passport init sample app

Things worth calling out

This is an intentionally very simple sample app.

Other things to consider:

• Sample app is updated with new SDK changes
• Updated public documentation with new SDK changes (Immutable X and Immutable zkEVM)
• [n/a] Sample game is updated with new SDK changes
• [n/a] Replied to GitHub issues