Add alaveteli to services that the deploy user can restart

Also reorganise these sections a bit and update them to reflect the fact
that you can now generate purge-varnish using the config_files task.
Arguably it should be:

```diff
-* `daemon_name`: The name of the daemon. Set this to `purge-varnish`.
+* `daemon_name`: The name of the daemon. This is set by the rake task.
```