feat(docker): enhance Dockerfile with entrypoint script and additional packages

- Added `su-exec` to the Docker image for improved user switching.
- Introduced a custom entrypoint script to manage container startup.
- Ensured the creation of necessary directories with appropriate permissions.
- Updated health check configurations for better reliability.

deploy/docker/cfdm/docker-entrypoint.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+set -eu
+
+mkdir -p /data
+
+if [ "$(id -u)" = "0" ]; then
+  chown -R node:node /data 2>/dev/null || true
+  chmod -R u+rwX /data 2>/dev/null || true
+  if su-exec node sh -c 'touch /data/.write-test && rm -f /data/.write-test'; then
+    exec su-exec node "$@"
+  fi
+  echo "cfdm: /data is not writable by user node after chown; starting as root" >&2
+fi
+
+exec "$@"