Dockerfile: remove aufs-tools, as it's not available on bullseye

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Dockerfile

@@ -252,7 +252,6 @@ RUN --mount=type=cache,sharing=locked,id=moby-dev-aptlib,target=/var/lib/apt \
     --mount=type=cache,sharing=locked,id=moby-dev-aptcache,target=/var/cache/apt \
         apt-get update && apt-get install -y --no-install-recommends \
             apparmor \
-            aufs-tools \
             bash-completion \
             bzip2 \
             iptables \

Dockerfile.simple

@@ -36,7 +36,6 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 		xfsprogs \
 		xz-utils \
 		\
-		aufs-tools \
 		vim-common \
 	&& rm -rf /var/lib/apt/lists/*