More automation for system installation

http://webangel.com.br/linux/instalando-nginx-php-mysql-postfix-phpmyadmin-wordpress-5-minutos

I was reading above review (using Google translator).

Can we automate postfix configuration step?

Also a random mysql password + http://rtcamp.com/tutorials/mysql/mycnf-preference/

Goal is, as usual, to automate everything that can be automated!
