This screen informs the user that the burn has completed and that the
drive can be ejected directly.
It also provides a button to burn another image without exitting the
application.
Fixes: https://github.com/resin-io/herostratus/issues/41
Currently we only pass the drive device. By passing all the object
(containing the mountpoint, size, etc) we allow more control to the
writer in how to treat the device before/during/after the burning
process.
