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/Microsoft/hcsshim/.gitattributes

@@ -0,0 +1,3 @@
+* text=auto eol=lf
+vendor/** -text
+test/vendor/** -text