feat: migrate purelb to ArgoCD (#84)

Migrate PureLB load balancer from Terragrunt to ArgoCD/Kustomize.
Deploys purelb v0.13.0 with two LBNodeAgent and two ServiceGroup CRs
(common: 198.18.200.0/24, dmz: 198.18.199.0/24).
Adds LBNodeAgent and ServiceGroup to kubeconform skip list (no CRD catalog schema).

💘 Generated with Crush

Assisted-by: Claude Sonnet 4.6 via Crush <crush@charm.land>

Reviewed-on: #84

argocd/projects/platform.yaml

@@ -12,6 +12,7 @@ spec:
     - https://cloudnative-pg.github.io/charts
     - https://helm.elastic.co
     - https://helm.releases.hashicorp.com
+    - https://purelb.github.io/purelb/charts
     - https://intel.github.io/helm-charts/
     - https://kubernetes-sigs.github.io/external-dns/
     - https://releases.rancher.com/server-charts/stable
@@ -34,6 +35,8 @@ spec:
       server: https://kubernetes.default.svc
     - namespace: 'node-feature-discovery'
       server: https://kubernetes.default.svc
+    - namespace: 'purelb'
+      server: https://kubernetes.default.svc
     - namespace: 'puppet'
       server: https://kubernetes.default.svc
     - namespace: 'reposync'
@@ -55,6 +58,8 @@ spec:
       kind: ValidatingWebhookConfiguration
     - group: 'scheduling.k8s.io'
       kind: PriorityClass
+    - group: 'purelb.io'
+      kind: '*'
     - group: 'nfd.k8s-sigs.io'
       kind: NodeFeatureRule
     - group: 'deviceplugin.intel.com'