fix-license task should check if file starts with #cloud-config, and if so, put the license header after that line

[jacobbmay]

Currently the fix-license task will put the header at the beginning of a cloud-config template. This causes cloud-init to not use the cloud-config contents at startup.

This can be a frustrating issue to try to resolve for someone that starts using this task in a repo since you can end up with VMs that start successfully and look healthy, but can't be accessed since the users in the cloud-config aren't being set up.

Looks like it already checks for #! in bash files and puts the license after that, so I imagine it isn't a huge ask to have it check for #cloud-config as well.