migrate central server to new AWS account

• create instance
• add instance to chake configuration
• install all software (with chake/itamae)
• do a first rsync of files
• plan a maintainance window
• during the maintainance window: disable the workers
• during the maintainance window: copy the database
• during the maintainance window: do a final rsync of files
• during the maintainance window: switch DNS to new server
• during the maintainance window: wait for DNS changes to propagate to all workers
• during the maintainance window: reenable workers