[Security] Make Alpine image compliant with CIS Docker Community Edition Benchmark v1.1.0.

Current alpine image is not compliant with CIS Docker Community Edition Benchmark v1.1.0. Section **4 - Container Images and Build File**
Please refer to [docker/docker-bench-security](https://github.com/docker/docker-bench-security.

To reproduce issues

> docker pull alpine:latest

> docker run --net host --pid host --userns host --cap-add audit_control -e DOCKER_CONTENT_TRUST=1 -v /var/lib:/var/lib -v /var/run/docker.sock:/var/run/docker.sock -v /usr/lib/systemd:/usr/lib/systemd -v /etc:/etc --label docker_bench_security docker/docker-bench-security:latest -t "alpine:latest" -e "check_[12367].*|check_5.[1-57-9].*"

Specially, but maybe not only, (COPY should not be used anymore. Use COPY instead.)

> [INFO] 4.9 - Ensure COPY is used instead of ADD in Dockerfile
> [INFO] * ADD in image history: [alpine:latest]