add .gitlab-ci.yml for continuous platform tests

.platformtest-ci/download_ci_file.bash

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd "$(dirname "${BASH_SOURCE[0]}")"
+
+commit="$1"
+build="$2"
+src="$3"
+dst="$4"
+
+[ -n "$commit" -a -n "$build" -a -n "$src" -a -n "$dst" ] || ( echo "arguments must not be empty"; exit 1 )
+
+aws="aws --endpoint-url https://minio.cschwarz.com --no-sign-request"
+
+
+path="s3://zrepl-ci-artifacts/$commit/$build/$src"
+$aws s3 cp "$path" "$dst"