Refer to https://review.openstack.org/#/c/399354/ Change-Id: I934ff074cb795b971f79ecce008931cc672f1932 Partially-implements: blueprint condition-pre-check
* Merge prechecks.yml and site.yml playbook * Create empty precheck.yml into all roles. Change-Id: I8a138558a26c0a2a66c5fd48ed37be657c99c1dd Implements: blueprint condition-pre-check