Add RDAP warning when domain searches by nameserver may be incomplete

When searching for domains by nameserver name or IP address, we fetch the matching nameserver keys, then search for domains by those keys. We limit the number of nameserver keys returned, to avoid arbitrarily large domain queries. This CL adds a warning to the RDAP response if we retrieved the maximum number of nameservers. This may indicate that we have not found all the domains.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168885124

java/google/registry/rdap/RdapIcannStandardInformation.java

@@ -105,6 +105,24 @@ public class RdapIcannStandardInformation {
   static final ImmutableList<ImmutableMap<String, Object>> TRUNCATION_NOTICES =
       ImmutableList.of(TRUNCATED_RESULT_SET_NOTICE);
 
+  /**
+   * Used when a search for domains by nameserver may have returned incomplete information because
+   * there were too many nameservers in the first stage results.
+   */
+  static final ImmutableMap<String, Object> POSSIBLY_INCOMPLETE_RESULT_SET_NOTICE =
+      ImmutableMap.<String, Object>of(
+          "title",
+          "Search Policy",
+          "description",
+          ImmutableList.of(
+              "Search results may contain incomplete information due to first-stage query limits."),
+          "type",
+          "result set truncated due to unexplainable reasons");
+
+  /** Possibly incomplete notice as a singleton list, for easy use. */
+  static final ImmutableList<ImmutableMap<String, Object>> POSSIBLY_INCOMPLETE_NOTICES =
+      ImmutableList.of(POSSIBLY_INCOMPLETE_RESULT_SET_NOTICE);
+
   /** Included when the requester is not logged in as the owner of the domain being returned. */
   static final ImmutableMap<String, Object> DOMAIN_CONTACTS_HIDDEN_DATA_REMARK =
       ImmutableMap.<String, Object> of(