Refactor container build and installation pipeline to use configurable Makefile parameters (e.g. DISTROS, base images) and propagate them through all build, install, and test scripts

scripts/build/build-image.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+source "${SCRIPT_DIR}/resolve-base-image.sh"
+
+for distro in $DISTROS; do
+  base_image="$(resolve_base_image "$distro")"
+
+  echo ">>> Building test image for distro '$distro' (BASE_IMAGE=$base_image)..."
+
+  docker build \
+    --build-arg BASE_IMAGE="$base_image" \
+    -t "package-manager-test-$distro" \
+    .
+done