Add instance option 'confirmation_required' that will require that an option shows a confirmation prompt

Hi team,

Is this feature something that you would consider incorporating into RailsAdmin? A confirmation prompt seems like something that would be commonly required - I certainly need it in the app I'm building, currently.

If you are ok with the idea of this feature, I plan to add in some specs and incorporate I18n so that you can customise the confirmation prompt per action/model.