write the boto/ec2 provider backend

[rizumu]

Some hooks are already in place, but it would be nice for someone with more ec2 experience to get involved on this one.

ubuntu images: http://uec-images.ubuntu.com/releases/

fedora images: https://fedoraproject.org/wiki/Cloud_images

arch linux images: https://wiki.archlinux.org/index.php/Arch_Linux_AMIs_for_Amazon_Web_Services

debian images: http://wiki.debian.org/Cloud/AmazonEC2Image

tips on creating images: http://blog.elliottcable.name/posts/arch_linux_and_ec2.xhtml