Need to add Heat-based OSTF test with deploy many virtual machines

We have cool test suite with OSTF tests in Fuel, but this is no end.

Fuel can deploy OpenStack on many compute nodes and we have no OSTF tests, which allow to validate that all Compute nodes are operational.

The simplest method to validate it - deploy Heat stack with many virtual machine with 'm1.tiny' flavor and verify that this Heat stack will be deployed successfully.

We should track count of compute nodes, count of active virtual machines, parameters of compute nodes and OpenStack quotas to detect the normall count of virtual machines.