dockerfile: add nasm (necessary for x264)

docker/Dockerfile_debian_10

docker/Dockerfile_debian_10_arm64

docker/Dockerfile_debian_10_armhf

docker/Dockerfile_debian_10_i386

docker/Dockerfile_debian_9

docker/Dockerfile_debian_9_armhf

docker/Dockerfile_debian_9_i386

docker/Dockerfile_fedora_27

docker/Dockerfile_fedora_28

docker/Dockerfile_fedora_29

docker/Dockerfile_fedora_30

docker/Dockerfile_fedora_31

docker/Dockerfile_fedora_32

docker/Dockerfile_opensuse-leap_15.1

docker/Dockerfile_raspbian_10_armhf

docker/Dockerfile_rhel_8

make-ring.py