Add command to extract build info from metadata

This will allow to recreate the metadata after patching the FS.

PUBLISHED_FROM=dae228bbf49d71f383e4dc52316cf98aba3914f5

docs/items.json

@@ -0,0 +1,6 @@
+{
+  "items": [
+    { "type": "section", "name": "usage-example" },
+    { "type": "section", "name": "design-concept" }
+  ]
+}