schema: Stop vendoring minio

[cgwalters]

It's a huge dependency, and everything in schema/ gets
re-vendored again at the toplevel and in mantle.

The minio stuff is a dependency of gangplank which we're not
building right now.

Instead of minio, I want to make a push to use OCI artifacts
to store coreos-assembler metadata.

[dustymabe]

Wow. I thought we had already dropped minio by stopping building gangplank. The diff is really hard to follow here because there are so many files. For my education, what exactly did you do here (i.e. the steps you took to get this diff)?

[cgwalters]

Basically

$ cd schema
$ <write code changes to drop minio deps>
$ go mod tidy && go mod vendor
$ cd ../mantle
$ go mod tidy && go mod vendor

To review from the Github UI, you should see a file panel on the left. You can collapse the vendor/ directories - this will show just the changed files in schema/*.go.

[cgwalters]

Now, I think what we really want to do is kill off the schema/ module, move the logic to the toplevel, and switch to have mantle/ vendor the toplevel.

[dustymabe]

To review from the Github UI, you should see a file panel on the left. You can collapse the vendor/ directories - this will show just the changed files in schema/*.go.

cool. I trust you. Thanks for tracking this down. I wonder how much space savings we get because of this.

[jmarrero]

lgtm