pkg/nimble: derive used address type in statconn from peer address
pkg/nimble: derive used address type in statconn from peer address

Using a `BLE_ADDR_RANDOM` as the peer address type allows connecting only to peers that have a static random address. Deriving the peer address type from the peer address is simple and allows connections to be established with peers that have either a public or
static random address.
RIOT-OS/RIOT,jasonatran/RIOT,kaspar030/RIOT,kYc0o/RIOT,ant9000/RIOT,jasonatran/RIOT,jasonatran/RIOT,ant9000/RIOT,kYc0o/RIOT,kaspar030/RIOT,ant9000/RIOT,ant9000/RIOT,RIOT-OS/RIOT,miri64/RIOT,kYc0o/RIOT,miri64/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,kYc0o/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,miri64/RIOT,kaspar030/RIOT,ant9000/RIOT,miri64/RIOT