Tibor Vass 416b7bb23f install/uninstall: allow aliasing buildx to `docker builder`
Currently the user can type `docker buildx` to use this tool.
This patch allows the user to install buildx as a `docker builder` alias.

As an additional benefit, this allows the regular `docker build` to hook
into `buildx build`.

Note that the install and uninstall commands are currently hidden.

Signed-off-by: Tibor Vass <tibor@docker.com>
..
candidate.go vendor: initial vendor
cobra.go vendor: initial vendor
error.go vendor: initial vendor
manager.go install/uninstall: allow aliasing buildx to `docker builder`
manager_unix.go vendor: initial vendor
manager_windows.go vendor: initial vendor
metadata.go vendor: initial vendor
plugin.go vendor: initial vendor
suffix_unix.go vendor: initial vendor
suffix_windows.go vendor: initial vendor