Added tests for pseudo params

To cover 'OS::stack_id' and 'OS::stack_name'.

Change-Id: Idbaf867f71feacb4a1f382eb7233fb69517603a9
Rename the remaining instance group tests for clarity

In preparation to move these tests to functional tests rename and
document what they do.
This also simplifies the launch config test as it does not need
the scaling group for this test.

Part of blueprint decouple-nested
Change-Id: I77d7fb38b852590a3004532d28b9b9fcf29dc819
Adds multi-region support for stack resource

Adds new resource type called OS::Heat::Stack which allows
creating new stack in specified region using heatclient.

Implements: blueprint multi-region-support

Co-Authored-By: Qiming Teng <tengqim@cn.ibm.com>

Change-Id: I62cb07877702c57dd0e77dbcb0e123a3ec2c885d
Merge "Rename the remaining instance group tests for clarity"
Merge "Added tests for pseudo params"
Merge "Adds multi-region support for stack resource"