feat: add fuse-overlayfs storage driver for Docker-in-Docker

- Install fuse-overlayfs package in Dockerfile
- Configure Docker daemon to use fuse-overlayfs storage driver
- Add daemon.json configuration in entrypoint.sh
- Update documentation in README.md and README.es.md

This enables Docker-in-Docker to work efficiently in unprivileged
containers without requiring the overlay2 driver.

Dockerfile

@@ -30,7 +30,7 @@ RUN set -eux; \
   apt-get upgrade -y && \
   apt-get install --no-install-recommends -y \
     bash bash-completion ca-certificates curl dbus default-jre doas dos2unix dumb-init file \
-    fuse3 gh git gnupg golang iproute2 iptables jq lsb-release lsof make nano net-tools nodejs npm \
+    fuse3 fuse-overlayfs gh git gnupg golang iproute2 iptables jq lsb-release lsof make nano net-tools nodejs npm \
     openssh-client passwd patch pipx python3 python3-pip python3-venv shellcheck siege \
     sudo tar tree uidmap unzip virtualenv wget xz-utils; \
   \