Fixed itests to work with new savannaclient

* python-savannaclient 0.5 breaks compatibility with old its usage
  in integration tests
* added parameter Tenant ID for OpenStack to tests
* new initialisation method was added using single entrypoint
* removed savanna_url since it has wrong pattern and it's not needed
  anymore in this case
* other parameters cleanups are TBD, this fix is mostly to fix
  integration tests running
* savanna.job_executions.create call updated due to the removal of
  job_exec_data argument

Co-Authored-By: Sergey Lukjanov <slukjanov@mirantis.com>

Change-Id: I48e86cf486da354c1615602f084246d11b6a4670