REFACTOR(argocd): separate image-updater manifests

- Move ExternalSecrets to image-updater-manifests folder
- Add manifests source to image-updater Application
- Remove unnecessary ignoreDifferences from argocd

argocd/manifests/image-updater-secret.yaml

@@ -1,50 +0,0 @@
-apiVersion: external-secrets.io/v1
-kind: ExternalSecret
-metadata:
-  name: zot-registry-credentials
-  namespace: argocd
-spec:
-  refreshInterval: 1h
-  secretStoreRef:
-    kind: ClusterSecretStore
-    name: vault-backend
-  target:
-    name: zot-registry-credentials
-    creationPolicy: Owner
-    template:
-      type: kubernetes.io/dockerconfigjson
-      data:
-        .dockerconfigjson: |
-          {"auths":{"zot0213.kro.kr":{"username":"{{ .USERNAME }}","password":"{{ .PASSWORD }}","auth":"{{ printf "%s:%s" .USERNAME .PASSWORD | b64enc }}"}}}
-  data:
-    - secretKey: USERNAME
-      remoteRef:
-        key: zot
-        property: USERNAME
-    - secretKey: PASSWORD
-      remoteRef:
-        key: zot
-        property: PASSWORD
----
-apiVersion: external-secrets.io/v1
-kind: ExternalSecret
-metadata:
-  name: github-creds
-  namespace: argocd
-spec:
-  refreshInterval: 1h
-  secretStoreRef:
-    kind: ClusterSecretStore
-    name: vault-backend
-  target:
-    name: github-creds
-    creationPolicy: Owner
-  data:
-    - secretKey: username
-      remoteRef:
-        key: github
-        property: username
-    - secretKey: password
-      remoteRef:
-        key: github
-        property: password