Various stats commands

[ghost]

!bot stats

Mostly just cus I think it's neat. Show system RAM% and, if implemented, roll macro usage. Show total dice rolled and commands requested over life of bot.

Inspired by rad admin panels: https://github.com/epicmaxco/vuestic-admin

UPDATE: Using Supervisor to solve #47 will give us this, the bot just has to curl itself. Alternately, this would be fun to code...