Add EKS documentation for deployer.

[naemono]

While debugging an EKS/AWS issue, I found the documentation for the EKS deployer to be missing. This simply updates the documentation with the common options needed to deploy an EKS cluster.

[prodsecmachine]

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[Copilot]

Pull Request Overview

This PR adds comprehensive documentation for deploying EKS clusters using the deployer tool. The documentation was previously missing, making it difficult for developers to understand how to set up EKS deployments.

• Added EKS section with installation and setup instructions
• Included AWS profile configuration and credential requirements
• Documented region customization options through configuration file

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