Linux support for build scripts

This commit modifies create-akanda-raw-image.sh to configure/install akanda-appliance on
debian machines. It also includes multiple cleanups of files that are no longer needed.
Disable fsck on booth and setup ssh key/root password
Add net.ipv6.conf.all.forwarding=1 sysctl
Merge pull request #66 from jordant/linux

Linux raw build script