heat tests : add parse_stack function to test utils

Add convenience function parse_stack to utils so it can be
reused in test to avoid duplication

Change-Id: I608e2227c695a9faecbd8ff78a1339b47174a006
heat tests : convert most tests to inline templates

Convert to inline minimal templates, to remove dependency on
in-tree templates which we plan to remove.  Note there are still
some more tests remaining which need similar changes (shardy todo)

Change-Id: I0864d1f15ea3b815d449277387440157f104bbf3
heat tests : separate Autoscaling and CW alarm tests

Currently the AutoScaling test also tests the CloudWatch Alarm
resource, so separate out the CW Alarm test to simplify things

Change-Id: Ia346ee49f3a363e2d63e801c74265545d7af1acf
Merge "heat tests : add parse_stack function to test utils"
Merge "heat tests : convert most tests to inline templates"
Merge "heat tests : separate Autoscaling and CW alarm tests"