Upgrade system, migrate cobbler data from old container to new

During cluster deployment, orchestrator registers nodes
in cobbler, cobbler keeps all this information in file
system based database which is in /var/lib/cobbler/config
directory, we have to migrate this directory from one
container to another.

We have the next data migartion flow for cobbler
* take /var/lib/cobbler/config from previous container
* save it in working directory in
  /var/lib/fuel_upgrade/version/cobbler_configs
* mount /var/lib/fuel_upgrade/version in container
  as /tmp/upgrade
* right after cobbler container is created, copy
  cobbler data from mounted directory to
  /var/lib/cobbler/config

blueprint upgrade-to-5-1
Closes-bug: #1331975
Change-Id: I6a3a20831ef1aa85a90da64e7c2c1434a9ae59a1