add(qemu): Initial stab at some documentation for QEMU virtual machines.

This covers using a brand new qemu wrapper script so don't push this to
the production website until a version that includes the new script (v48
or later) has been pushed to dev-channel.
fix(ec2): Update AMI to 50.0.0
Merge pull request #8 from marineam/master

add(qemu): Initial stab at some documentation for QEMU virtual machines.