cobrautil: decouple from bake/build dependency chain

[crazy-max]

#3646 was not enough because cobrautil imports bake which imports build package so let's decouple this as well.

[tonistiigi]

Not against this update, but what is importing cobrautil, so that we need to reduce its dependencies?

[crazy-max]

Would like to call history.BuildName in Desktop Build backend to avoid drifting. But atm history package imports completion:

buildx/commands/history/open.go

Line 7 in c423bc7

"github.com/docker/buildx/util/cobrautil/completion"

Which imports bake:

buildx/util/cobrautil/completion/completion.go

Line 6 in c423bc7

"github.com/docker/buildx/bake"

Which imports build:

buildx/bake/bake.go

Line 24 in c423bc7

"github.com/docker/buildx/build"

But can't import build package because of BuildKit session export changes for cloud driver:

go: github.com/docker/desktop-build/pkg/buildmanager imports
	github.com/docker/buildx/commands/history imports
	github.com/docker/buildx/util/cobrautil/completion imports
	github.com/docker/buildx/bake imports
	github.com/docker/buildx/build imports
	github.com/moby/buildkit/session/export: module github.com/moby/buildkit@latest found (v0.28.0), but does not contain package github.com/moby/buildkit/session/export

[tonistiigi]

We should move BuildName out of commands then as the cli commands packages are not for importing.

[tonistiigi]

Is this still needed or should be closed?

[crazy-max]

Is this still needed or should be closed?

I think it still makes sense to decouple but I'm fine closing it if you prefer.