Remove legacy scripts for building docker images

[ci skip]

qa/bin/docker

-#!/bin/sh
-
-case "$1" in
-    build)
-        docker pull $CI_REGISTRY_IMAGE:latest
-        docker build --cache-from $CI_REGISTRY_IMAGE:latest \
-          -t $CI_REGISTRY_IMAGE:ce-latest -t $CI_REGISTRY_IMAGE:ee-latest \
-          -t $CI_REGISTRY_IMAGE:ce-nightly -t $CI_REGISTRY_IMAGE:ee-nightly \
-          -t $CI_REGISTRY_IMAGE:latest .
-        ;;
-    publish)
-        test -n "$CI_BUILD_TOKEN" || exit 1
-        docker login --username gitlab-ci-token --password $CI_BUILD_TOKEN registry.gitlab.com
-        docker push $CI_REGISTRY_IMAGE:latest
-        docker push $CI_REGISTRY_IMAGE:ce-latest
-        docker push $CI_REGISTRY_IMAGE:ee-latest
-        docker push $CI_REGISTRY_IMAGE:ee-nightly
-        docker push $CI_REGISTRY_IMAGE:ee-nightly
-        docker logout registry.gitlab.com
-        ;;
-    *)
-        echo "Usage: $0 [build|publish]"
-        exit 1
-        ;;
-esac