dns: add generic dns_query() function
dns: add generic dns_query() function

kYc0o/RIOT,jasonatran/RIOT,kYc0o/RIOT,kYc0o/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,ant9000/RIOT,miri64/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,ant9000/RIOT,miri64/RIOT,kaspar030/RIOT,kYc0o/RIOT,kaspar030/RIOT,ant9000/RIOT,miri64/RIOT,miri64/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,miri64/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,kaspar030/RIOT,jasonatran/RIOT,jasonatran/RIOT,jasonatran/RIOT,ant9000/RIOT,kaspar030/RIOT,ant9000/RIOT