Currently we use both Thor and Rake for `bin/rails` commands.
We eventually want to get all the built-ins task promoted to Thor Commands.
This migrates the `restart` task to Thor.

With this change it also possible to restart outside the application
directory:

```bash
blog/bin/rails restart
```

Co-authored-by: Hartley McGuire <skipkayhil@gmail.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>