xci: kubespray: Switch kubespray to dynamic inventory

xci: kubespray: Switch kubespray to dynamic inventory

The kubespray installer contains one inventory per flavor. We can get
rid of these files and use the dynamic inventory similar to OSA.
Moreover, we extend the dynamic inventory to read additional group
variables per flavor if necessary. This way we can still pass additional
information to inventory on per-flavor basis. This also fixes a typo
in the 'IDF' file. We also need to bump Ansible for kubespray since the
version we were using is having troubles with dynamic inventories.

Change-Id: Ic58101555f81aec5fee3c193608440aa89bbe445
Signed-off-by: Markos Chandras <mchandras@suse.de>