xci: Use local playbooks for XCI deployments

xci: Use local playbooks for XCI deployments

Previously, we used to clone the releng-xci repository under a directory
in /tmp, copy our changes to that repository and then run the
xci-deploy.sh script from it. However, this made things far too complex
for deployers and developers since some playbooks were used from the
local repo whereas others were used from teh /tmp checkout. By running
everything from our local repository simplifies things a lot since we
can directly test our changes and also reduces the code we have in our
playbooks.

Change-Id: If16aa51b2846c170676df82d25cb90e26b1568b2
Signed-off-by: Markos Chandras <mchandras@suse.de>