Provide "repo" alternative for Windows users

Googles "repo" ist only available for Unix users, so Windows users can't make use of its funtionality to clone all Maven repositories at once. Their only chance is to manualy clone all repositories in the exact same directory strucuture.

It would be great if we can also provide a script for Windows users.

Start by locating the existing Unix "repo" script and examining how it clones the Maven repositories and preserves their directory structure. A Windows-compatible script is done when Windows users can clone all repositories at once with the same structure; verify it on a Windows environment.

Written by the indexing model from the issue text.