[6.x] Database Orders: Store status log in its own table

[duncanmcclean]

This pull request moves the order status log out of the order's data column and into a database table of it's own.

This change will make things much easier in terms of querying orders made on a certain date with a certain status. In the previous way of doing things, that was near impossible.

To Do

• Upon upgrade, users should publish the migration
• Upon upgrade/deployment, users should migrate status log from orders table
• Ensure the sc:migrate-to-database command imports the status log properly

[github-actions]

Released as part of v6.0.0.