[Docs] Documenting Kanvas Support for Exported Kubernetes Pods

#### Current State

A new documentation page under (Getting Started with Designer](https://docs.layer5.io/kanvas/getting-started/) entitled, “Starting from Existing Infrastructure” is needed.

#### Desired State

With Kanvas now supporting the rendering of exported Kubernetes pods using the kubectl command:
```bash
kubectl get pods -n -o yaml > exported-pods.yaml
```

We want to provide clear and comprehensive documentation that helps users quickly get started. This will allow them to experience firsthand how powerful Kanvas is in visualizing and managing Kubernetes resources. The goal is to ensure a smooth onboarding process and showcase the efficiency of this new capability.

Documentation of the following questions, too:

1. What's the upper limit of components that can be ingested?
1. What effect do the number of relationships definitions have on this?

This update should identify that `kubectl describe` is not currently supported.

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