Add limit to list_domains command

This allows list_domains to continue working for large TLDs.

TESTED=Deploys to alpha and it works to list the most recently created domains even
on a TLD with a huge number of domains on it (much more than .app has currently).

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=196717389

java/google/registry/tools/server/ListObjectsAction.java

@@ -107,6 +107,7 @@ public abstract class ListObjectsAction<T extends ImmutableObject> implements Ru
       // Get the object data first, so we can figure out the list of all available fields using the
       // data if necessary.
       ImmutableSet<T> objects = loadObjects();
+      logger.infofmt("Loaded %d objects.", objects.size());
       // Get the list of fields we should return.
       ImmutableSet<String> fieldsToUse = getFieldsToUse(objects);
       // Convert the data into a table.