Rename all tables we use in Queue plugin to be started with _

[donhardman]

Proposal:

As we discussed earlier, we should rename our system-created tables in the queue plugin to start with an underscore. They should also be prefixed with the plugin name, so all tables should follow the format queue[something]. This fulfills our decision.

Checklist:

^{To be completed by the assignee. Check off tasks that have been completed or are not applicable.}

• Task estimated
• Specification created, reviewed and approved
• Implementation completed
• Tests developed
• Documentation updated
• Documentation proofread
• Changelog updated
• OpenAPI YAML updated and issue created to rebuild clients