This required a lot of re-implementation of how garage gets interacted
with, including updating cluster layout using the admin API and
initialization of the global bucket key.
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.
The new code makes it a lot clearer what the sources of each
file/directory is, and makes it more difficult to forget to add a file
or directory. This will be helpful when it comes to bootstrapping an
entire network, which will require yet a third way of generating
bootstrap files.
