Add new system tests for murano

- Add system tests which check murano
  on HA mode with neutron gre

Change-Id: I771139f7d7f1f96540a687b48a62f70c2dbbcdc8
Implements-blueprint: additional-system-tests-for-murano
Add new system tests for sahara

- Add system tests which check sahara
  on HA mode with neutron gre

Change-Id: I03bd59ca55a05ccfac18229f571b4fd90743bd2e
Implements-blueprint: additional-system-tests-for-sahara
Add method which returns cluster public VIP by id

When we want to connect to OpenStack services API which
are running on HA cloud, we need to have ability to get public
virtual IP address of deployed environment. So adding an
additional method to the FuelWebClient class for that.

Related-bug: #1369412
Change-Id: I98c8c323dd81f0b361b73050df29083e0d912211
Merge "Add method which returns cluster public VIP by id"
Merge "Add new system tests for murano"
Merge "Add new system tests for sahara"