Fix prometheus-sample-app deployment with build instructions

[SurweeshSP]

Problem

The prometheus-sample-app deployment YAML had an empty image: "" field, which prevented users from successfully deploying the sample application. This caused confusion as there were no instructions on how to obtain or build the required image.

Solution

• Replaced empty image field with example image name: prometheus-sample-app:latest
• Added detailed comments explaining how to build the image from source
• Included direct link to the sample app source code in aws-otel-community repository
• Provided a quick one-line Docker build command for convenience
• Added imagePullPolicy: IfNotPresent to prevent image pull errors when using locally built images

Changes Made

• Updated examples/eks/aws-prometheus/prometheus-sample-app.yaml
• Added comprehensive inline documentation for building the sample app image

Testing

The YAML structure remains valid and users now have clear instructions to:

1. Build the image from the provided source repository
2. Deploy the sample app successfully to their EKS cluster

Related

This improves the developer experience for users testing ADOT with Prometheus metrics on EKS.

[github-actions]

This PR is stale because it has been open 30 days with no activity.