Support package AKS Flex (Unbounded CNI) deployment using Helm

Currently, the installation of the Unbounded CNI stack for AKS Flex relies on running a sequence of imperative `kubectl apply` commands on pre-rendered YAML manifests, alongside manual shell script steps (e.g., handling `$SPLIT_DIR`).
To align with cloud-native best practices, improve maintainability, and allow seamless integration with our GitOps/CD pipelines, we should package these components into a single, configurable **Helm Chart**.

We need to create a local Helm chart (e.g., `unbounded-net`) that encapsulates all the resources currently applied manually.

The chart should be structured as follows:
* **`templates/crds/`**: To host the Custom Resource Definitions (CRDs) so they can be managed and upgraded by Helm.
* **`templates/`**: For standard resources (`Namespace`, `ConfigMap`, `ServiceAccount`, `RBAC`, `Controller` Deployment, and the site-specific `DaemonSet`).
* **`values.yaml`**: To parameterize dynamic values like image tags, repository paths, and site-specific configurations.

The possibile issues/notes:
* **Server-Side Apply:** The installation documentation must specify the use of the `--enable-server-side-apply` flag during `helm upgrade --install` to mimic the original `--server-side --force-conflicts` behavior. Support directly only Helm 4?
* **DaemonSet Templating:** Replace the dynamic `$SPLIT_DIR/daemonset-aks-site.yaml` approach by templating the DaemonSet and injecting site-specific parameters via `values.yaml`.
* **CRDs** : verify the CRDs upgrade via helm because it's problematic with helm 3.

Start by inventorying the pre-rendered YAML manifests and imperative kubectl steps currently used for installation, including the $SPLIT_DIR/daemonset-aks-site.yaml flow. Build the chart around templates/crds/, templates/, and values.yaml, covering the listed resources and site-specific DaemonSet parameters. Done means the chart supports helm upgrade --install with --enable-server-side-apply, documents that flag, and verifies the CRD upgrade behavior, especially with Helm 3.

Written by the indexing model from the issue text.