I installed ISPConfig on Digital Ocean's $5 deal. The server has 1GB of memory, but 74% of it is already used up after installing ISPConfig. It is probably running a lot of unnecessary services that I need to get rid of. All I really need is Apache, MySQL and maybe some Firewall type services, the rest can go. I don't need a mail server at all. How do I strip down my ISPConfig server to the essentials only?