Move docker build stuff into a subdirectory. Update structure to retire manual-{pre,post}

docker/Dockerfile.bookworm

@@ -0,0 +1,25 @@
+FROM debian:bookworm
+ARG DEBIAN_FRONTEND=noninteractive
+ARG VPP_INSTALL_SKIP_SYSCTL=true
+ARG REPO=release
+EXPOSE 22/tcp
+RUN apt-get update && apt-get -y install curl procps tcpdump iproute2 iptables \
+  iputils-ping net-tools git python3 python3-pip vim-tiny openssh-server bird2 \
+  mtr-tiny traceroute && apt-get clean
+
+# Install VPP
+RUN mkdir -p /var/log/vpp /root/.ssh/
+RUN curl -s https://packagecloud.io/install/repositories/fdio/${REPO}/script.deb.sh |  bash
+RUN apt-get update && apt-get -y install vpp vpp-plugin-core && apt-get clean
+
+# Build vppcfg
+RUN pip install --break-system-packages build netaddr yamale argparse pyyaml ipaddress
+RUN git clone https://github.com/pimvanpelt/vppcfg.git && cd vppcfg && python3 -m build && \
+    pip install --break-system-packages dist/vppcfg-*-py3-none-any.whl
+
+# Config files
+COPY files/etc/vpp/* /etc/vpp/
+COPY files/etc/bird/* /etc/bird/
+COPY files/init-container.sh /sbin/
+RUN chmod 755 /sbin/init-container.sh
+CMD ["/sbin/init-container.sh"]