Add support for annotations and labels in spec. (#739)

```
stack: webapp-deployer-backend
deploy-to: k8s
annotations:
  foo.bar.annot/{name}: baz
labels:
  a.b.c/{name}.blah: "value"
```

Reviewed-on: cerc-io/stack-orchestrator#739
Co-authored-by: Thomas E Lackey <telackey@bozemanpass.com>
Co-committed-by: Thomas E Lackey <telackey@bozemanpass.com>

stack_orchestrator/deploy/webapp/undeploy_webapp_from_registry.py

@@ -147,6 +147,7 @@ def command(ctx, laconic_config, deployment_parent_dir,
 
     previous_requests = load_known_requests(state_file)
     requests.sort(key=lambda r: r.createTime)
+    requests.reverse()
 
     # Find deployments.
     deployments = {}