Sequelize Cleanup

[FancMa01]

Clean up Sequelize

1. Only one migration for one model
2. Any migration to alter the table must check if the alteration has already been completed
3. A proper relationship is established, so action cascades from parent to child

Notes - Deleting Application must delete all associated resources
Deleting Cluster - should not cascade to JM or any other monitoring. Instead, a warning should be displayed explaining any monitoring, or workflows with this cluster ID will fail. This gives users the option to update clusters in existing monitoring and workflows