Ansible installer update

  * Moved Ansible to version 2.10
  * Python Virtual env
  * New option to use a custom SSH key
  * Use of cloud-init file supported
  * Increased the number of options to be passed to the remote installer

Change-Id: I70131f1a24707656c9390445df91d17abab95763
Signed-off-by: Antonio Marsico <antonio.marsico@bt.com>