organize overlays by stages instead of envs

Signed-off-by: Kent <kent.rancourt@gmail.com>

stages/uat/kustomization.yaml

@@ -0,0 +1,15 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+- ../../base
+- configmap.yaml
+
+patches:
+- target:
+    kind: Service
+    name: kargo-demo
+  patch: |-
+    - op: replace
+      path: /spec/ports/0/nodePort
+      value: 30082