Fixing Vagrant cluster provisioning (#4218)

* Pass ansible_ssh_user as host_var

Co-authored-by: Damian Darczuk <damian.darczuk@intel.com>
Co-authored-by: Paweł Pałucki <pawel.palucki@intel.com>

* Create a directory before downloading container images to ansible host

Co-authored-by: Damian Darczuk <damian.darczuk@intel.com>
Co-authored-by: Paweł Pałucki <pawel.palucki@intel.com>

* Set private key usuing synchronize task options

Co-authored-by: Damian Darczuk <damian.darczuk@intel.com>
Co-authored-by: Paweł Pałucki <pawel.palucki@intel.com>