The defaults conflicts with the defaults of `services.httpd`:
```
error: The option `nodes.machine.services.logrotate.enable' has conflicting definition values:
- In `/home/thomas/Workspace/Packaging/nixpkgs/nixos/modules/profiles/minimal.nix': false
- In `/home/thomas/Workspace/Packaging/nixpkgs/nixos/modules/services/web-servers/apache-httpd/default.nix': true
Use `lib.mkForce value` or `lib.mkDefault value` to change the priority on any of these definitions.
(use '--show-trace' to show detailed location information)
```
`nixos/profile/minimal` is not used in the majority of the tests and it does not
seem to have a specific reason to use it for the HAProxy test.
Refactor the systemd service definition for the haproxy reverse proxy,
using the upstream systemd service definition. This allows the service
to be reloaded on changes, preserving existing server state, and adds
some hardening options.
