Add tree back to systemd container

custom/testing/ubuntu-22.04-systemd.Dockerfile

@@ -9,11 +9,13 @@ COPY 01_nodoc /etc/dpkg/dpkg.cfg.d/01_nodoc
 #
 # apt-utils was required by golden states, this may/should be fixed in those
 # states.
+#
+# tree is used by workflows for debugging
 RUN apt update -y \
   && echo 'tzdata tzdata/Areas select America' | debconf-set-selections \
   && echo 'tzdata tzdata/Zones/America select Phoenix' | debconf-set-selections \
   && DEBIAN_FRONTEND="noninteractive" apt install -y \
-  tar wget xz-utils apt-utils init systemd
+  tree tar wget xz-utils apt-utils init systemd
 
 # Set the root password, this was done before single user mode worked.
 # RUN echo "root\nroot" | passwd -q root