Added a snippet for the Counter App 🧮

[moazelsawaf]

Hello Nash 👋🏻

In this PR, I have added a new snippet to create the famous Counter App, which is the official Flutter Demo almost since flutter was born. 💙

The main goal of having this snippet is because a lot of docs and tutorials are using the Counter App as an example, so the learner may want to remove and recreate the initial Counter App multiple times, and here comes the role of this snippet 💪🏻

NOTE: The snippet creates the Counter App without the comments provided in the official code to make it simple and clean ✅

That's it 👌🏻💙

Thanks 🙏🏻
Moaz El-sawaf

[moazelsawaf]

@Nash0x7E2
Any Updates?