consider option to (re)arrange repos into subdirs by github type

[salewski]

For example:

    private/sources/${repo}
    private/mirrors/${repo}
    private/archived/${repo}

    public/sources/${repo}
    public/forks/${repo}
    public/mirrors/${repo}
    public/archived/${repo}

Misc notes:

• Public forks cannot be made private (though you can duplicate a repo and then make the duped repo private)

[salewski]

Replaced label type:feature with the label type:idea; this is not fleshed-out enough to implement.