Add helper to get nmcli connection apath by ifname
    
    Resolves: bz1919052
    Upstream: Fedora
    Conflict: None
    
    commit c69578ca431998d7460d40e58769a05b58bab0e8
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Thu Apr 1 15:32:09 2021 +0800
    
        Add helper to get nmcli connection apath by ifname
    
        apath (a D-Bus active connection path) is used for nmcli connection operations, e.g.
          $ nmcli connection show $apath
    
        Signed-off-by: Coiby Xu <coxu@redhat.com>
        Acked-by: Kairui Song <kasong@redhat.com>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>