Moved nginx settings to plugin.

These settings shouldn't be in the profile template, as they only make sense when used with nginx.
If you're using nginx, you can enable the nginx plugin.

plugins/available/nginx.plugin.bash

@@ -1,6 +1,12 @@
 cite about-plugin
 about-plugin 'manage your nginx service'
 
+# Set the path nginx
+export NGINX_PATH='/opt/nginx'
+
+# Add nginx to the path
+export PATH=$PATH:$NGINX_PATH/sbin
+
 function nginx_reload() {
   about 'reload your nginx config'
   group 'nginx'