Docs for how to use custom images under runner/ directory

What would you like added?

it's really unclear how to use these images, where do i get them from and how they go into the helm chart? i tried just putting summerwind/actions-runner-dind:v2.313.0-ubuntu-20.04-a68aa00 under the spec in my runner set but im getting an init error. are there docs on how to use them? and how to modify them for example if i do need something like helm, awscli etc.?

A clear and concise description of what you want to happen.

Note: Feature requests to integrate vendor specific cloud tools (e.g. awscli, gcloud-sdk, azure-cli) will likely be rejected as the Runner image aims to be vendor agnostic.

Why is this needed?

to be able to understand better how to use the custom images
A clear and concise description of any alternative solutions or features you've considered.

Additional context

here are my value files for the runner set:
gha-runner-scale-set:
githubConfigUrl: "https://github.com/***"

githubConfigSecret: "arc-secret"

minRunners: 5

runnerGroup: "k8s-arc-runners"
runnerScaleSetName: "ubuntu-dind-16g"

containerMode:
type: "dind"

template:
spec:
tolerations:
- key: karpenter-managed-type
operator: Equal
value: arc-scalers
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: karpenter-managed-type
operator: In
values:
- arc-scalers
containers:
- name: runner
image: summerwind/actions-runner-dind:v2.313.0-ubuntu-20.04-a68aa00
command: [ "/home/runner/run.sh" ]
resources:
requests:
memory: "8Gi"
cpu: "2"
limits:
memory: "16Gi"
cpu: "4"

Add any other context or screenshots about the feature request here.

Start with the custom images under the runner/ directory and the Helm chart values shown in the report. Document where the images come from, how to configure them in a runner scale set, and how to customize them without vendor-specific integrations. The work is done when users can configure a custom image and understand the supported customization path.