Code review comment for ~xnox/maas-images:master

@blake-rouse - You can use proposed-images-manual in the CI. You can set the git repo although the images branch must be on master(we should fix that).

@xnox - lp:maas-images is taking the images that CPC generates on http://cloud-images.ubuntu.com/ and creates a stream for MAAS. The image itself(the SquashFS file) is exactly what CPC produces. All lp:maas-images is doing is chrooting into the image with a memfs overlay to get the kernel and initrd. Since the MAAS ephemeral environment needs additional resources in the initrd we cannot rely on what is in packaging. We try to keep the changes minimal from the image CPC produces. Typically a new series only requires modifying meph-v3.yaml.

When the images are being produced CPC does generate each image on the distro series that is being produced(e.g xenial are produced on xenial, bionic on bionc, etc). We keep everything in one branch to ease development and because its always been that way.