Restore a revision

Add a button/option on the Revisions tab to allow users restore a particular version.

An idea to explore is that clicking on that button should fill all the fields of the current draft on the client side so users can review and make changes before saving, or discard the changes by simply refreshing the page. If that brings too much complexity then we can just replace the data in the `beacon_pages` table.

That action must display a confirmation dialog.

Start at the Revisions tab entry point and inspect how revision data relates to the beacon_pages table. Trace how the current draft is loaded and saved, then determine the restore flow and confirmation dialog behavior. The work is done when a user can select a revision, confirm the action, and review or apply the restored data.

Written by the indexing model from the issue text.