package: create debian package with prebuilds

The generated variants include raspi and non-raspi platforms.

.github/ci/build-env

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+if [[ $# -gt 2 ]]; then
+  echo "usage: $0 <buster|bullseye> <amd64|arm32v7|arm64v8>"
+  exit 1
+fi
+
+docker_image="camera_streamer_build_env"
+
+debian_version="bullseye"
+[[ -n "$1" ]] && debian_version="$1" && docker_image="${docker_image}_${1}"
+
+docker_arch=""
+[[ -n "$2" ]] && docker_arch="$2/" && docker_image="${docker_image}_${2}"
+
+PWD=$(pwd)
+ROOT=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )/../.." &> /dev/null && pwd)
+
+set -xeo pipefail
+
+docker build -t "$docker_image" \
+  --build-arg "DOCKER_ARCH=$docker_arch" \
+  --build-arg "DEBIAN_VERSION=$debian_version" \
+  --build-arg BUILD_TYPE \
+  --target build_env - < .github/ci/Dockerfile
+
+exec docker run --rm -it -u "$UID" -v "$ROOT:$ROOT" -w "$ROOT" "$docker_image"