Initialize /config from /etc, except for existing files (like bind-mounts). Move to using /config in VPP, even though there is a backwards compat symlink from /etc/{frr,bird,vpp} to /config

docker/Dockerfile

@@ -10,7 +10,7 @@ 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 \
-  mtr-tiny traceroute && apt-get clean
+  mtr-tiny traceroute rsync && apt-get clean
 
 # Install VPP - sideload from local debs if --build-context vppdebs=<path> is provided,
 # otherwise install from packagecloud. Debs are bind-mounted and never stored in a layer.
@@ -47,8 +47,6 @@ RUN curl -s -o /usr/share/keyrings/cznic-labs-pkg.gpg https://pkg.labs.nic.cz/gp
 
 # Config files
 COPY files/etc/ /etc/
-RUN mkdir /config \
-    && for i in vpp bird frr; do mv /etc/$i /config/$i; ln -sf /config/$i /etc/$i; done
 COPY files/init-container.sh /sbin/
 RUN chmod 755 /sbin/init-container.sh
 CMD ["/sbin/init-container.sh"]