skip unit copies on content view promotion
As part of content view promotion, we can skip unit copy as we use the yum-clone-distributor as part of the publish. This will require http://projects.theforeman.org/issues/21548 as well as special handling of reindexing and republishing of content view version repos.
Fixes #21549 - do not actually copy units on promotion
this change modifies promotions and the 2nd half
of content view publishes to not actually copy any units
to the target repositories. This works fine, but breaks the rule
that we can simply republish a repository to get its content.
Now, since the repositories in pulp have no actual content
we have to always use the yum_clone_distributor when generating
metadata via the various methods of doing that.
The benefit is a decrease in promotion time down to
seconds, and and a decrease in publish time by approximately