Use localhost for app_with_roles and 127.0.0.1 for app. Confirm we can
deploy both and the respond to requests. Ensure the proxy is removed
once both have been removed.
1. Update to kamal-proxy 0.4.0 which creates and chowns
/home/kamal-proxy/.config/kamal-proxy to kamal-proxy
2. Use a docker volume rather than mapping in a directory, so docker
keeps it owned by the correct user
The proxy can be enabled via the config:
```
proxy:
enabled: true
hosts:
- 10.0.0.1
- 10.0.0.2
```
This will enable the proxy and cause it to be run on the hosts listed
under `hosts`, after running `kamal proxy reboot`.
Enabling the proxy disables `kamal traefik` commands and replaces them
with `kamal proxy` ones. However only the marked hosts will run the
kamal-proxy container, the rest will run Traefik as before.
