Use ReplaySpecializer to fix DomainBase replays (#991)

* Use ReplaySpecializer to fix DomainBase replays

DomainBase currently has a number of ancillary objects that require a
cascading delete that doesn't get propagated.  Implement beforeSqlDelete() in
DomainContent to delete these child entities.

* Remove unnecessary Query variable

* Fix rebase error

db/src/main/resources/sql/flyway/V87__fix_super_domain_fk.sql

@@ -0,0 +1,20 @@
+-- Copyright 2021 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 "Host" DROP CONSTRAINT fk_host_superordinate_domain;
+ALTER TABLE if exists "Host"
+    ADD CONSTRAINT fk_host_superordinate_domain
+    FOREIGN KEY (superordinate_domain)
+    REFERENCES "Domain"(repo_id)
+    DEFERRABLE INITIALLY DEFERRED;