mirrormanager: install scan-primary-mirror
    
    scan-primary-mirror is another MirrorManager2 tool rewritten in Rust.
    
    The main advantage is that the path to repository mapping is no longer
    part of the code, but it is part of the configuration file which makes
    it much easier to add new repository definition.
    
    As with all other rewritten tools in Rust it uses considerably less
    memory.
    
    Signed-off-by: Adrian Reber <adrian@lisas.de>