core: add columns to machine table, bump to v5

core/data/schema/versions/CORE_4_rollback.sql

@@ -0,0 +1,3 @@
+ALTER TABLE machine DROP COLUMN memo;
+ALTER TABLE machine DROP COLUMN is_blacklisted;
+ALTER TABLE machine DROP COLUMN `data`;

core/data/schema/versions/CORE_5_upgrade.sql

@@ -0,0 +1,3 @@
+ALTER TABLE machine ADD memo varchar(255) NULL;
+ALTER TABLE machine ADD is_blacklisted tinyint(1) NULL;
+ALTER TABLE machine ADD `data` longtext NULL;