Revert "Remove DatabaseMigrationStateSchedule (#1689)" (#1698)

This reverts commit 18d51738ce.

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

@@ -242,6 +242,12 @@
         primary key (scope, type)
     );
 
+    create table "DatabaseMigrationStateSchedule" (
+       id int8 not null,
+        migration_transitions hstore,
+        primary key (id)
+    );
+
     create table "DelegationSignerData" (
        algorithm int4 not null,
         digest bytea not null,