Deploy Apps to Nomad-based Setup

We have refactored the repository to use a Docker-based setup for development and deployment. The current (legacy) version of the apps is live from the [`prod`](https://github.com/freeCodeCamp/demo-projects/tree/prod) branch. The `prod` branch may receive selected hot patches as we work through the full migration.

Here is a task list for the same:

```[tasklist]
### Tasks
- [ ] https://github.com/freeCodeCamp/demo-projects/issues/404
- [ ] https://github.com/freeCodeCamp/demo-projects/issues/405
- [ ] ...
```

Note that the contributing guide will be updated eventually; if you are looking for instructions on working on the legacy version, please visit the guide on the `prod` branch.