Ensure present/latest for puppet driven package updates

Ensure present/latest for puppet driven package updates

This change updates yum_update.sh so that we set set a boolean
output when "managed" packages should get updated. The
output is named 'update_managed_packages' and for the
puppet implementation it is wired up so that it
directly sets tripleo::packages::enable_upgrade to
control whether packages are updated.

It also modifies yum_update.sh to build a yum update excludes list for
packages managed by puppet. The exclude lists are being
generated via puppet-tripleo as well via the new 'write_package_names'
function that is now wired into all the role manifests.

This change does not actually trigger the puppet apply. The fix for
Related-Bug: #1463092 will be used to trigger the puppet run when the
hiera changes. As a minor tweak to this logic we append the
UpdateIdentifier to the config_identifier so that we ensure
puppet gets executed on an update where other (non-related)
hiera changes also occur.

Co-Authored-By: Dan Prince <dprince@redhat.com>
Change-Id: I343c3959517eae38bbcd43648ed56f610272864d