refactor(argocd): migrate Crossplane management to ApplicationSet with sync waves

Replaces single Application with an ApplicationSet to manage resources by sync wave.
Removes outdated kustomization.yaml and legacy Argo CD sync annotations from provider manifests.

Author: wnqueiroz

argocd/crossplane-system.yaml

@@ -1,36 +1,48 @@
 apiVersion: argoproj.io/v1alpha1
-kind: Application
+kind: ApplicationSet
 metadata:
   name: crossplane-system
   namespace: argocd-system
 spec:
-  project: default
-  source:
-    repoURL: "git@github.com:wnqueiroz/platform-engineering-backstack.git"
-    targetRevision: feature-argocd # TODO: change to main
-    path: crossplane
-    kustomize: {}
-  destination:
-    server: https://kubernetes.default.svc
-    namespace: crossplane-system
-  syncPolicy:
-    automated:
-      prune: true
-      selfHeal: true
-    syncOptions:
-      - SyncWaveOrder=true
-    retry:
-      limit: 5
-      backoff:
-        duration: 5s
-        factor: 2
-        maxDuration: 1m
-  ignoreDifferences:
-    - group: "hooli.tech"
-      kind: "XQueueClaim"
-      jsonPointers:
-        - "/metadata"
-    - group: "hooli.tech"
-      kind: "XQueue"
-      jsonPointers:
-        - "/metadata"
+  generators:
+    - list:
+        elements:
+          - name: providers
+            path: crossplane/providers
+            wave: "0"
+          - name: providers-config
+            path: crossplane/providers-config
+            wave: "1"
+          - name: functions
+            path: crossplane/functions
+            wave: "2"
+          - name: compositions
+            path: crossplane/compositions/aws
+            wave: "3"
+          - name: xrds
+            path: crossplane/xrds
+            wave: "4"
+          - name: claims
+            path: crossplane/claims
+            wave: "5"
+
+  template:
+    metadata:
+      name: crossplane-{{name}}
+      annotations:
+        argocd.argoproj.io/sync-wave: "{{wave}}"
+    spec:
+      project: default
+      source:
+        repoURL: git@github.com:wnqueiroz/platform-engineering-backstack.git
+        targetRevision: feature-argocd # TODO: change to main
+        path: "{{path}}"
+        directory:
+          recurse: true
+      destination:
+        server: https://kubernetes.default.svc
+        namespace: crossplane-system
+      syncPolicy:
+        automated:
+          prune: true
+          selfHeal: true

crossplane/kustomization.yaml

@@ -5,8 +5,6 @@ kind: ProviderConfig
 metadata:
   name: default
   namespace: crossplane-system
-  annotations:
-    argocd.argoproj.io/sync-wave: "-1"
 spec:
   endpoint:
     url:

crossplane/providers-config/localstack-provider-config.yaml

@@ -3,7 +3,5 @@ kind: Provider
 metadata:
   name: provider-aws-sqs
   namespace: crossplane-system
-  annotations:
-    argocd.argoproj.io/sync-wave: "-2"
 spec:
   package: xpkg.upbound.io/upbound/provider-aws-sqs:v1.21.1