cloud: rework package list, add comments
    
    This reworks the package list to add comments and remove some things
    that didn't need to be explicitly removed.
    
    - remove +systemd-udev -> already included by default
    - remove -biosdevname -> not included by default
    - remove -iprutils -> not included by default
    - remove -uboot-tools -> not included by default
    
    There are no packages added or removed from the built cloud image as
    part of this change. Just updating the input package list to be more
    meaningful.