Docker Toolbox is not available anymore

[markus-becker-tridonic-com]

Describe the bug

https://openthread.io/guides/border-router/docker#mac_or_windows has a link to Docker Toolbox (https://docs.docker.com/toolbox/) which now redirects users to https://docs.docker.com/desktop/. If the user then installs Docker Desktop and uses it, the RCP dongle mounted into the docker image is only a directory and ot-br-posix does not work.

Expected behavior

Either clearly document that Docker Mac and Windows does not work for now and direct users to installing ot-br-posix from source on Mac (Windows?) or find a way how it works with Docker Desktop.

[markus-becker-tridonic-com]

Related to https://github.com/openthread/ot-br-posix/issues/1347.