fix(helm): add global.security.allowInsecureImages for bitnamilegacy images

The new Bitnami Helm charts (postgresql 12.1.5, zookeeper 13.8.7, etc.)
include image signature verification that rejects non-standard images
like bitnamilegacy. This causes Helm install to fail with:

  ERROR: Original containers have been substituted for unrecognized ones.
  Unrecognized images: docker.io/bitnamilegacy/zookeeper:3.9.3-debian-12-r21

Setting global.security.allowInsecureImages: true allows the use of
bitnamilegacy images with the newer chart versions.

Reference: bitnami/charts#30850

Author: zhan7236

deploy/kubernetes/dolphinscheduler/README.md

@@ -12,6 +12,7 @@ Please refer to the [Quick Start in Kubernetes](../../../docs/docs/en/guide/inst
 
 | Key | Type | Default | Description |
 |-----|------|---------|-------------|
+| global.security.allowInsecureImages | bool | `true` | Allow using non-standard container images (required for bitnamilegacy images). This is required because the new Bitnami charts verify image signatures. |
 | alert.affinity | object | `{}` | Affinity is a group of affinity scheduling rules. If specified, the pod's scheduling constraints. More info: [node-affinity](https://kubernetes.io/docs/concepts/scheduling-eviction/assign-pod-node/#node-affinity) |
 | alert.annotations | object | `{}` | You can use annotations to attach arbitrary non-identifying metadata to objects. Clients such as tools and libraries can retrieve this metadata. |
 | alert.customizedConfig | object | `{}` | configure aligned with https://github.com/apache/dolphinscheduler/blob/dev/dolphinscheduler-alert/dolphinscheduler-alert-server/src/main/resources/application.yaml |

deploy/kubernetes/dolphinscheduler/values.yaml

@@ -19,6 +19,12 @@
 # This is a YAML-formatted file.
 # Declare variables to be passed into your templates.
 
+# -- Global settings for Bitnami subcharts
+global:
+  security:
+    # -- Allow using non-standard container images (required for bitnamilegacy images)
+    allowInsecureImages: true
+
 # -- World time and date for cities in all time zones
 timezone: "Asia/Shanghai"