Migrate test_server_cfn_init to tempest clients

Migrate the test and change OrchestrationScenarioTest used by the test.
This is a part of the migrating all scenario tests to using tempest own
clients.

Change-Id: Iafc1b021fe8a9a5daa0e2d7eef0542b7929c415a
Partially-implements: bp:tempest-client-scenarios
Merge "Migrate test_server_cfn_init to tempest clients"