update the registries.json spec

spec/registries.json.md

@@ -63,15 +63,25 @@ this:
       "tokens": {
         "push": "/path/to/public/engines/push/token.json"
       },
-      "tls-verify": true
+      "tls-verify": true,
+      "quay": {            # optional quay object that is used for quay specific things -- which at this time is all image expiration related (this was in rickshaw-settings.json but it should probably be migrated hear)
+        "expiration-length": "2w",
+        "refresh-expiration": {
+          "token-file": "/path/to/public/engines/refresh/expiration/token.json",
+          "api-url": "https://quay.io/api/v1/repository/crucible/client-server"
+        }
+      }
     },
     "private": {
       "url": "foo.com/crucible/private-engines",
       "tokens": {          # it is entirely possible (even likely?) that the push and pull token files may be the exact same file, but by specifying them separately the option to use separate tokens is preserved (which may be desirable since the pull token will need to be distributed to the endpoints)
         "push": "/path/to/private/engines/push/token.json",
         "pull": "/path/to/private/engines/pull/token.json"
       },
-      "tls-verify": true
+      "tls-verify": true,
+      "quay": {            # this could also have an optional quay object as above
+        ...
+      }
     }
   },
   "userenvs": [            # this array would contain information to be provided to workshop so it would know how to access base userenv images that have controlled access (by matching against the url?)