The `bootstrap/creator` package is gone, almost as quickly as it
arrived. The `Bootstrap` type is now able to write its own tgz file, and
the two places where bootstrap files are being created pull the data
down to do so and create the `Bootstrap` structs directly.
The structure of the bootstrap file itself has been changed, now there's
just a single `hosts` directory which contains files which are yaml
encodings of the `Host` type, rather than having it be split into
`nebula` and `garage` directories. This makes creating bootstrap files a
lot easier.
Host types have been moved within the `bootstrap` package.
Refactored how boostrap FS is interacted with. There is now a
`Bootstrap` struct which has pre-loaded all data within the bootstrap
FS. This helps centralize the logic around reading the data (though not
yet completely).
Choosing of the garage node to interact with no longer occurs in like
three different places. It occurs at the environment level now, and is
aided by the new `garage.Peer` type.