Support Generating ZTP from Switch Spec

Summary

This issue proposes expanding the Switch CR so ZTP can be generated directly from the Switch.spec, rather than relying only on static ZTP templates or a complete ConfigMap script.

For example, the generated ZTP flow would declaratively start generic Docker containers defined in the Switch object.

Basic example

This example is just a Switch illustration to start the discussion.

  volumes:
  - name: dbus
    hostPath:
      path: /var/run/dbus
      type: Directory
  - name: sonic-version
    hostPath:
      path: /etc/sonic/sonic_version.yml
      type: File

  containers:
  - name: sonic-agent
    image: ghcr.io/ironcore-dev/sonic-agent:latest
    command:
    - /switch-agent-server
    args:
    - -port
    - "57400"
    securityContext:
      runAsUser: 0
    volumeMounts:
    - name: dbus
      mountPath: /var/run/dbus
    - name: sonic-version
      mountPath: /etc/sonic/sonic_version.yml
      readOnly: true

  - name: wirelet
    image: ghcr.io/ironcore-dev/wirelet-sonic:latest
    args:
    - --name
    - leaf-1
    - --interface
    - leaf-1-eth0-0,leaf-1-eth1-0

The provisioning server would render the required Docker commands from this API. Container names, images, commands, arguments, volumes, and volume mounts follow familiar Kubernetes Pod concepts, while the implementation remains SONiC ZTP plus Docker.