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/model/EppResource.java

@@ -83,6 +83,7 @@ public abstract class EppResource extends BackupGroupRoot implements Buildable {
   // Map the method to XML, not the field, because if we map the field (with an adaptor class) it
   // will never be omitted from the xml even if the timestamp inside creationTime is null and we
   // return null from the adaptor. (Instead it gets written as an empty tag.)
+  @Index
   CreateAutoTimestamp creationTime = CreateAutoTimestamp.create(null);
 
   /**