Dockerfile: added less and vim

If you are using kas interactivly vim and less are very convenient
tools to have.

Signed-off-by: Claudius Heine <ch@denx.de>

Dockerfile

@@ -14,7 +14,8 @@ RUN apt-get update && \
                        chrpath socat cpio python python3 rsync \
                        tar bzip2 curl dosfstools mtools parted \
                        syslinux tree python3-pip bc python3-yaml \
-                       lsb-release python3-setuptools ssh-client && \
+                       lsb-release python3-setuptools ssh-client \
+                       vim less && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*