Manager: drop the job_storage_infos database table

GORM Automigration created a separate `job_storage_infos` table (because
we used it wrong, to be fair), which is actually only used as an
embedded struct in the `jobs` table. This means this table itself can be
dropped.

internal/manager/persistence/migrations/0002_drop_job_storage_infos.sql

@@ -0,0 +1,9 @@
+-- GORM Automigration created a separate `job_storage_infos` table (because we
+-- used it wrong, to be fair), which is actually only used as an embedded struct
+-- in the `jobs` table. This means this table can be dropped.
+--
+-- +goose Up
+DROP TABLE `job_storage_infos`;
+
+-- +goose Down
+CREATE TABLE `job_storage_infos` (`shaman_checkout_id` varchar(255) DEFAULT "");