Create a dialog to confirm File Storage actions

[apburnes]

When a user creates a destructive action in the File Storage service, there should be a dialog component to notify customers

Acceptance Criteria

• Use USWDS as much as possible
• Have parent control state and click actions through callbacks/handlers
• Require only header and primary button, all other enhancements optional
• Modal is dismissable by default, but can be made non-dismissable (force interaction) via a bool prop
• Modal opens and closes via a bool prop (similar to HTML5 Dialog element)
• Modal is accessible (focus trap, labels, etc)
• Modal is modular/re-usable

[sknep]

@apburnes I added the acceptance criteria that made sense to me -- feel free to review the PR and AC and lmk what you think.