Create a converter for sets of InetAddresses and use it in HostResource (#612)

* Create a converter for sets of inetAddresses and use it in HostResource

This can just be a set of strings where each string represents an
address;  there's no need for it to be a separate table. This allows
for simplification of the SQL schema.

* Regenerate golden SQL file after renaming v28 -> v29

* Add more tests and rename a typo in the file

* Refactor common test code and use tm methods

* Use JUnit5 API

* Rename test entity

db/src/main/resources/sql/flyway/V30__inet_address_converter.sql

@@ -0,0 +1,17 @@
+-- Copyright 2020 The Nomulus Authors. All Rights Reserved.
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+
+AlTER TABLE "HostResource" ADD COLUMN inet_addresses text[];
+
+DROP TABLE IF EXISTS "HostResource_inetAddresses";