build: We don't need to run the ansible playbook anymore
Add a 'releases' command to the cli
Fix the cli entry-point
Create the output dir before syncing in if necessary.

This also makes it so that people can comment out the rsync_in_objs option to
disable this feature.
Make it so we can comment out the rsync options to disable the feature
Update our directory structure to match production
Have the mock group own /srv/fedora-atomic instead of the rpmostreecompose user

The rpmostreecompose user is currently provided by the rpm-ostree-toolbox
package, which we no longer rely on.
Remove the obsolete ansible playbook
Update our cli usage in the readme