d2vm: smaller ubuntu base images

full example: enable serial auto login

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

templates/ubuntu.Dockerfile

@@ -3,17 +3,15 @@ FROM {{ .Image }}
 USER root
 
 RUN apt-get update -y && \
-  apt-get -y install \
-  linux-image-virtual
-
-
-RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-      systemd-sysv \
-      systemd \
-      dbus \
-      udhcpc \
-      iproute2 \
-      iputils-ping
+  DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends \
+  linux-image-virtual \
+  initramfs-tools \
+  systemd-sysv \
+  systemd \
+  dbus \
+  udhcpc \
+  iproute2 \
+  iputils-ping
 
 RUN systemctl preset-all