Issue #3335061 by sekinet, yas: Add test cases for OpenStack Heat (CRUD)

...s/cloud_service_providers/openstack/openstack.routing.yml

...iders/openstack/src/Service/Rest/OpenStackServiceMock.php

...sts/mock_data/Functional/OpenStack/OpenStackStackTest.yml

...ures/templates/OpenStack-ATDD-03-15-OperateStacks.feature

.../src/Behat/features/templates/params/openstack_common.yml

...ack/tests/src/Functional/OpenStack/OpenStackStackTest.php

...s/openstack/tests/src/Traits/OpenStackTestEntityTrait.php

...openstack/tests/src/Traits/OpenStackTestFormDataTrait.php

...ers/openstack/tests/src/Traits/OpenStackTestMockTrait.php