Add SQL queries to RdapNameserverSearchAction (#987)

This has the same issue as the domain-search action where the database
ordering is not consistent between Objectify and SQL -- as a result,
there is one test that we have to duplicate in order to account for the
two sort orders.

In addition, there isn't a way to query @Convert-ed fields in Postgres
via the standard Hibernate / JPA query language, meaning we have to use
a raw Postgres query for that.

config/presubmits.py

@@ -211,6 +211,7 @@ PRESUBMITS = {
          # CriteriaQueryBuilder is a false positive
          "CriteriaQueryBuilder.java",
          "RdapDomainSearchAction.java",
+         "RdapNameserverSearchAction.java",
          "RdapSearchActionBase.java",
          },
     ):