Add a Sample Project to the repository's source code

[gumaciel]

Is your feature request related to a problem? If so, please describe.

Every time you want to develop on a new computer, you'll need to create a new project and then add addons, it's a lot of work.

What feature or improvement would you like to see?

Add a Sample Project to the repository's source code.

It can be a simple game.

Additional context

Note: The test/Example.tscn scene will continue to exist, it serves to test all possible AdMob calls