tapsetup: add capability to list bridges
tapsetup: add capability to list bridges

authmillenon/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,kYc0o/RIOT,authmillenon/RIOT,ant9000/RIOT,OlegHahm/RIOT,jasonatran/RIOT,OTAkeys/RIOT,kYc0o/RIOT,OTAkeys/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,ant9000/RIOT,OTAkeys/RIOT,authmillenon/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,ant9000/RIOT,ant9000/RIOT,kaspar030/RIOT,kYc0o/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,miri64/RIOT,OTAkeys/RIOT,kaspar030/RIOT,OlegHahm/RIOT,ant9000/RIOT,kaspar030/RIOT,authmillenon/RIOT,miri64/RIOT,authmillenon/RIOT,OlegHahm/RIOT,kaspar030/RIOT,jasonatran/RIOT,miri64/RIOT,kYc0o/RIOT,kYc0o/RIOT,miri64/RIOT,miri64/RIOT,authmillenon/RIOT,jasonatran/RIOT