StackRelease
The StackRelease resource is built and managed by the StackApps controller.
It is namespaced and contains the AppRevision that its controller will 
deploy and the relevant configuration taken from the StackAppConfig.
apiVersion: features.criticalstack.com/v1alpha1
kind: StackRelease
metadata:
  name: demoapp-v1
spec:
  appname: demoapp-v1
  apprevision: # nested AppRevision, see AppRevision docs.
  releaseconfig: # nested config for StackRelease. See StackAppConfig docs.