m/test/localregistry: use osbase/oci/registry

This replaces the localregistry implementation with a small wrapper
around the new registry package.

The images attribute of the Bazel rule was changed from a list to a
dict, which makes the repository and tag independent from the file path.

Change-Id: I1f6213dd67f7bdcf2373fe136958caa68b9f4d10
Reviewed-on: https://review.monogon.dev/c/monogon/+/4089
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/test/localregistry/spec/manifest.proto b/metropolis/test/localregistry/spec/manifest.proto
index d9cbeab..529c013 100644
--- a/metropolis/test/localregistry/spec/manifest.proto
+++ b/metropolis/test/localregistry/spec/manifest.proto
@@ -6,14 +6,16 @@
 
 // Single image metadata
 message Image {
-    // Name of the image (no domain or tag, just slash-separated path)
-    string name = 1;
-    // Path to the image
-    string path = 2;
+    // Repository where the image is served
+    string repository = 1;
+    // Tag where the image is served
+    string tag = 2;
+    // Path to the OCI layout directory containing the image
+    string path = 3;
 }
 
 // Main message
 message Manifest {
     // List of images for the local registry
     repeated Image images = 1;
-}
\ No newline at end of file
+}