consolidate file contents for cert manager

kubernetes/rpi5-cluster/apps/cert-manager/cert-manager.yaml

@@ -1,7 +1,7 @@
 apiVersion: kustomize.toolkit.fluxcd.io/v1
 kind: Kustomization
 metadata:
-  name: app
+  name: cert-manager
   namespace: cert-manager
 spec:
   interval: 1h
@@ -16,7 +16,7 @@ spec:
 apiVersion: kustomize.toolkit.fluxcd.io/v1
 kind: Kustomization
 metadata:
-  name: issuers
+  name: cert-manager-issuers
   namespace: cert-manager
 spec:
   interval: 1h
@@ -28,7 +28,7 @@ spec:
     namespace: flux-system
     name: home-cluster-ops
   dependsOn:
-    - name: app
+    - name: cert-manager
   postBuild:
     substituteFrom:
       - kind: Secret