Persist DomainBase.nsHosts VKeys to SQL (#541)

Persist nsHosts in Cloud SQL

Persist the VKey based nameserver hosts field of DomainBase in Cloud SQL with
foreign key constraints.

db/src/main/resources/sql/schema/db-schema.sql.generated

@@ -67,6 +67,11 @@
         primary key (repo_id)
     );
 
+    create table "DomainHost" (
+       domain_repo_id text not null,
+        ns_host_v_keys text
+    );
+
     create table "GracePeriod" (
        id  bigserial not null,
         billing_event_one_time bytea,
@@ -77,6 +82,27 @@
         primary key (id)
     );
 
+    create table "HostResource" (
+       repo_id text not null,
+        creation_client_id text,
+        creation_time timestamptz,
+        current_sponsor_client_id text,
+        deletion_time timestamptz,
+        last_epp_update_client_id text,
+        last_epp_update_time timestamptz,
+        statuses text[],
+        fully_qualified_host_name text,
+        last_superordinate_change timestamptz,
+        last_transfer_time timestamptz,
+        superordinate_domain bytea,
+        primary key (repo_id)
+    );
+
+    create table "HostResource_inetAddresses" (
+       host_resource_repo_id text not null,
+        inet_addresses bytea
+    );
+
     create table "Lock" (
        resource_name text not null,
         tld text not null,
@@ -222,6 +248,16 @@ create index reservedlist_name_idx on "ReservedList" (name);
        foreign key (revision_id) 
        references "ClaimsList";
 
+    alter table if exists "DomainHost" 
+       add constraint FKeq1guccbre1yk3oosgp2io554 
+       foreign key (domain_repo_id) 
+       references "Domain";
+
+    alter table if exists "HostResource_inetAddresses" 
+       add constraint FK6unwhfkcu3oq6q347fxvpagv 
+       foreign key (host_resource_repo_id) 
+       references "HostResource";
+
     alter table if exists "PremiumEntry" 
        add constraint FKo0gw90lpo1tuee56l0nb6y6g5 
        foreign key (revision_id)