Use pulp_deb optimize sync mode for most APT repo syncs
Optimize sync mode (the interface and basic idea is exactly the same as pulp_rpm optimize sync) was added in pulp_deb 2.20.0 (requires pulpcore 3.21).
Katello should take advantage of this feature for pulp_deb. ;-)
This will also fix the GUI interface for Debian "advanced sync" options (which currently talks about optimized sync and complete sync even though all APT syncs are currently effectively "complete syncs").