xci: Move OpenStack-Ansible out of the main script

xci: Move OpenStack-Ansible out of the main script

In preparation for supporting more NFVIs in XCI, we need to make the
main script NFVI agnostic. Right now, our NFVI is being deployed using
bifrost+OSA so we keep bifrost in the main script since the hardware
provisioning is NFVI agnostic (at least for now) but we move OSA to
its own directory. This should allow more NFVI to plug into XCI by
simply providing a nfvi-deploy.sh script. The user can select the
preferred NFVI using the XCI_NFVI variable.

Change-Id: Ieeacd3b22a64d363feff5d43ff23a80c39038837
Signed-off-by: Markos Chandras <mchandras@suse.de>