The publisher for cloud-images.ubuntu.com expects that artefacts
finishes with: file_url.endswith(project_prefix + suffix).
Now that we integrate app_id to the image name, we need thus to put it
before project_prefix and not between project_prefix and suffix.
On WSL, we have multiple applications with the same rootfs, but
different upgrade policy:
Ubuntu: should always track latest LTS and offer upgrade.
Ubuntu-<Version>: should never offer upgrade and will stick to Version
Ubuntu-Preview: current in development version.
Co-authored-by: Jean-Baptiste Lallement <jean-baptiste@ubuntu.com>
