Extend Weldr API to accept a list of denied image types, which should
not be exposed via API for any supported distribution. This
functionality will be needed to not expose image types which can't be
successfully built outside of Red Hat VPN. Example of such images are
the official RHEL EC2 images, which include RHUI client packages not
available publicly.
Image Types are filters when listing available compose types and
creating a new compose using Weldr API.
Extend osbuild-composer configuration to allow specifying the list of
denied Image Types for Weldr API.
Add unit tests for implemented changes.
Add NEWS entry describing the newly introduced functionality.
Signed-off-by: Tomas Hozza <thozza@redhat.com>