fedora-common-ostree: add archive repo to Silverblue

This is the culmination of a lot of work to make package layering
more reliable. This archive repo provides all packages that have
ever been in the updates repository, which means there should always
be a solution that will depsolve given the existing set of base layer
packages.

Pairing this along with coreos/rpm-ostree#2125
means that we should finally see less of the split base layer vs update
repo problem and see less `Forbidden base package replacements` errors.

For context see coreos/fedora-coreos-tracker#400

(cherry picked from commit 5ee6bce)

fedora-common-ostree.yaml

@@ -31,6 +31,9 @@ packages:
   # Contains default ostree remote config to be used on client's
   # system for fetching ostree update
   - fedora-repos-ostree
+  # the archive repo for more reliable package layering
+  # https://github.com/coreos/fedora-coreos-tracker/issues/400
+  - fedora-repos-archive
 
 selinux: true
 documentation: true