Add AWS Deployment Guide For WSO2 Identity Server

[DharshanSR]

Purpose

This PR adds a new AWS deployment guide for WSO2 Identity Server. The guide includes:

• Introduction page
• Prerequisites page
• Deployment architecture page

These pages provide users with comprehensive instructions for deploying WSO2 IS in AWS environments.

Related PRs

N/A

Test environment

• Documentation verified on local MkDocs environment

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines?
• Ran FindSecurityBugs plugin and verified report?
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets?

[CLAassistant]

All committers have signed the CLA.