roles/nginx: Remove nginx pre/post hooks

We are now using the well-known webroot.

roles/nginx/files/start-nginx.sh

@@ -1,3 +0,0 @@
-#!/usr/bin/env bash
-
-/bin/systemctl start nginx

roles/nginx/files/stop-nginx.sh

@@ -1,3 +0,0 @@
-#!/usr/bin/env bash
-
-/bin/systemctl stop nginx