Test cloud recovery after two controller nodes has been
power off and then power on
The test is using undercloud Ironic REST APIs to
power off/on overcloud controller nodes. It is using
the 'not soft' way, therefore it should be considered
an hard shutdown operation.
This patch should verify BugZilla n. 1942094 
Co-Authored-By: Slawek Kaplonski <email@example.com>