config: fix file/folder ownership

[crazy-max]

alternative and closes #2739

• fixes The Builds menu in docker desktop is not available for-mac#7454
• fixes Docker Desktop: Builders Application error for-mac#7356
• fixes Internal Server Error for-mac#7277
• fixes Internal server error when running docker for-mac#7362
• fixes Application Error We've reported this to our error tracker. Internal Server Error for-mac#7195
• fixes Docker Build - Internal Server Error - Application Issue Report for-mac#7144
• fixes (Docker desktop) Can't access to some pages anymore due to an Application error: "Internal server error" for-mac#7186
• fixes Docker Desktp > Docker Builds Showing Application Error / Images are not Building  for-mac#7309

When buildx runs through sudo, file and folder created are owned by root user. This is fine if HOME is not kept in /etc/sudoers config which is the default behavior on unix systems and would therefore write to /root but this is not the case on macOS:

Defaults        env_keep += "HOME MAIL"

$ sudo env|sort
HOME=/Users/crazymax
LOGNAME=root
MAIL=/var/mail/root
PATH=...
SHELL=/bin/sh
SUDO_COMMAND=/usr/bin/env
SUDO_GID=20
SUDO_UID=502
SUDO_USER=crazymax
TERM=xterm-256color
USER=root

Checked as well when using macos GitHub Runners:

If we try to create a builder with sudo, it would write with root owner in user's home:

$ sudo docker buildx create --name foo
foo
$ tree -pugfi ~/.docker/buildx
[drwx------ crazymax staff   ]  /Users/crazymax/.docker/buildx
[drwx------ crazymax staff   ]  /Users/crazymax/.docker/buildx/activity
[-rw------- crazymax staff   ]  /Users/crazymax/.docker/buildx/activity/desktop-linux
[-rw------- root     staff   ]  /Users/crazymax/.docker/buildx/activity/foo
[-rw------- crazymax staff   ]  /Users/crazymax/.docker/buildx/current
[drwx------ crazymax staff   ]  /Users/crazymax/.docker/buildx/defaults
[drwx------ crazymax staff   ]  /Users/crazymax/.docker/buildx/instances
[-rw------- root     staff   ]  /Users/crazymax/.docker/buildx/instances/foo

If we then try to remove this builder without sudo we got:

$ docker buildx rm foo
failed to remove foo: open /Users/crazymax/.docker/buildx/instances/foo: permission denied
ERROR: failed to remove one or more builders

Same if try to list builders:

$ docker buildx ls
ERROR: open /Users/crazymax/.docker/buildx/instances/foo: permission denied

To fix this issue and avoid changing file permissions like #2739, we need to check if buildx is running through sudo and set right owner when writing file or folder in configuration directory.