Port osbuild/images v0.33.0 with dot-notation to composer

Update the osbuild/images to the version which introduces "dot notation"
for distro release versions.

 - Replace all uses of distroregistry by distrofactory.
 - Delete local version of reporegistry and use the one from the
   osbuild/images.
 - Weldr: unify `createWeldrAPI()` and `createWeldrAPI2()` into a single
   `createTestWeldrAPI()` function`.
 - store/fixture: rework fixtures to allow overriding the host distro
   name and host architecture name. A cleanup function to restore the
   host distro and arch names is always part of the fixture struct.
 - Delete `distro_mock` package, since it is no longer used.
 - Bump the required version of osbuild to 98, because the OSCAP
   customization is using the 'compress_results' stage option, which is
   not available in older versions of osbuild.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

vendor/github.com/containers/storage/README.md

@@ -0,0 +1,46 @@
+`storage` is a Go library which aims to provide methods for storing filesystem
+layers, container images, and containers.  A `containers-storage` CLI wrapper
+is also included for manual and scripting use.
+
+To build the CLI wrapper, use 'make binary'.
+
+Operations which use VMs expect to launch them using 'vagrant', defaulting to
+using its 'libvirt' provider.  The boxes used are also available for the
+'virtualbox' provider, and can be selected by setting $VAGRANT_PROVIDER to
+'virtualbox' before kicking off the build.
+
+The library manages three types of items: layers, images, and containers.
+
+A *layer* is a copy-on-write filesystem which is notionally stored as a set of
+changes relative to its *parent* layer, if it has one.  A given layer can only
+have one parent, but any layer can be the parent of multiple layers.  Layers
+which are parents of other layers should be treated as read-only.
+
+An *image* is a reference to a particular layer (its _top_ layer), along with
+other information which the library can manage for the convenience of its
+caller.  This information typically includes configuration templates for
+running a binary contained within the image's layers, and may include
+cryptographic signatures.  Multiple images can reference the same layer, as the
+differences between two images may not be in their layer contents.
+
+A *container* is a read-write layer which is a child of an image's top layer,
+along with information which the library can manage for the convenience of its
+caller.  This information typically includes configuration information for
+running the specific container.  Multiple containers can be derived from a
+single image.
+
+Layers, images, and containers are represented primarily by 32 character
+hexadecimal IDs, but items of each kind can also have one or more arbitrary
+names attached to them, which the library will automatically resolve to IDs
+when they are passed in to API calls which expect IDs.
+
+The library can store what it calls *metadata* for each of these types of
+items.  This is expected to be a small piece of data, since it is cached in
+memory and stored along with the library's own bookkeeping information.
+
+Additionally, the library can store one or more of what it calls *big data* for
+images and containers.  This is a named chunk of larger data, which is only in
+memory when it is being read from or being written to its own disk file.
+
+**[Contributing](CONTRIBUTING.md)**
+Information about contributing to this project.