Add flatpak and cloud-initramfs-growroot packages to all boards
We will need both
cloud-initramfs-growroot to be added to the images built for all boards.
- flatpak is needed because we assume that folks will install flatpaks on any board they have (emulated or physical)
- cloud-initramfs-growroot is needed because we want the size of the partition to expand to fill the space of the install medium, rather than leave the image at a static 3.6GB.