FEATURE: Add caution before deleting Commons

[github-actions[bot]]

User Story

• As an admin
• I can see a "are you sure" popup when deleting a commons
• So that I don't accidentally delete an entire game in progress

Discussion

Currently, the Delete button on the commons page is a little dangerous.

If you click it, an entire commons goes away, with no confirmation dialog.

It would be better to add a modal (i.e. a popup) that asks the user: Are you sure you want to delete this commons?

The modal would have options such as [Permanently Delete] and [Keep this Commons].

Acceptance Criteria

• [x] If you click Delete on a commons, you get a modal, and the commons is not immediately deleted.
• [x] When you get the modal, if you click the [Keep this Commons] button, you are returned to the commons list page, and nothing is deleted
• [x] When you get the modal, if you click the [Delete this Commons] button, the commons is deleted.

Implementation Todos

An explanation of React Bootstrap modals can be found here: https://react-bootstrap.netlify.app/docs/components/modal/