Reworked SPT tests for running at MOS inside rally pod

These SPT tests are taken from the CVP-SPT, but reworked
to test MOS inside rally pod.

Here is the list of changes since CVP-SPT:
* Switched to Python3
* Removed all Salt related code
* Removed HW2HW test
* Default global_config.yaml is suitable for MOS
* Switched to iperf3
* Added smart waiters for VMs to be Active, VMs to be reachable by FIPs
* Extended pytest.ini file with logging settings
* Added lots of loggers at info level to understand what happends during the test run
* Extended & fixed README with the actual instruction
* Ability to use iperf3 even if there is no Internet at VMs
* Fixed the coding style according PEP8
* Various small fixes, enhancements

Change-Id: I31a1b8c8c827133d144377031c6f546d8c82a47d
diff --git a/global_config.yaml b/global_config.yaml
new file mode 100644
index 0000000..b297350
--- /dev/null
+++ b/global_config.yaml
@@ -0,0 +1,19 @@
+---
+# parameters for glance image test
+IMAGE_SIZE_MB: 9000
+
+# parameters for vm2vm test
+CMP_HOSTS: []
+image_name: "Ubuntu-18.04"
+flavor_name: 'spt-test'
+flavor_ram: 1536
+flavor_vcpus: 1
+flavor_disk: 5
+nova_timeout: 300
+external_network: 'public'
+iperf_prep_string: "sudo /bin/bash -c 'echo \"91.189.88.161        archive.ubuntu.com\" >> /etc/hosts'"
+internet_at_vms: 'true' # whether Internet is present at OpenStack VMs and iperf can be installed with apt
+iperf_deb_package_dir_path: '/artifacts/mos-spt/'
+iperf_time: 60 # time in seconds to transmit for (iperf -t option)
+ssh_timeout: 500
+skipped_nodes: []