[Feature Request]: add a demo app to give another approach of "getting started" to discover Tempest's functionalities

[gturpin-dev]

Description

As discussed on discord, it could be nice to have a "demo app" for Tempest docs.

Similar to https://github.com/symfony/demo or https://inertiajs.com/demo-application
this app could show how to build a basic app using Tempest's best practices
It can be a different approach to a "getting started" to help people discover Tempest's functionalities

Idk if this could be a separate app specifically built for this demo or just a link to Tempest's website code source ( like the stats using event sourcing ) or even links to @brendt YouTube lives where something is built with Tempest 🤷‍♂️

Benefits

Reduce the learning curve of Tempest 🎉