Remove kube-aggregator from OSS (#103659)

* feat: remove kube-aggregator for OSS and provide injection points with runner iface

* upgrade authlib to support expiresIn

* new FT

* new FT again

* update go.mod

* get rid of the slice implementation

* reconcile conflicts

* gracefully handle enterprise not being linked situation with kubeAggregator FT true

* allow dataplane agg and kube agg to both be added to delegate chain

* make update-workspace

* address feedback

* revert go.mod changes

* go.mod updates

* elaborate on why and how of skipping the Ready channel handling

* after rebase and make run

pkg/services/featuremgmt/toggles_gen.json

@@ -1695,6 +1695,22 @@
         "requiresRestart": true
       }
     },
+    {
+      "metadata": {
+        "name": "kubernetesAggregatorCapTokenAuth",
+        "resourceVersion": "1746996924159",
+        "creationTimestamp": "2025-05-11T20:48:13Z",
+        "annotations": {
+          "grafana.app/updatedTimestamp": "2025-05-11 20:55:24.159856 +0000 UTC"
+        }
+      },
+      "spec": {
+        "description": "Enable CAP token based authentication in grafana's embedded kube-aggregator",
+        "stage": "experimental",
+        "codeowner": "@grafana/grafana-app-platform-squad",
+        "requiresRestart": true
+      }
+    },
     {
       "metadata": {
         "name": "kubernetesClientDashboardsFolders",