Update guide - Decommission AWS account from Guardrails console

[rajlearner17]

Guide purpose
A clear and concise description of what the guide aims to achieve and why it's important.

Part of Guide > Governing AWS > https://turbot.com/guardrails/docs/guides/aws/decommission

• Update the format into new guide format with below use-cases

Cases

• If customer want do delete from guardrails as well as close account with AWS. (In this case you can simply Remove Account from action menu)
• If customer just want to off-board from Guardrails. ( We need to follow standard cleaning process by disabling few policies so that it cleans up the resources from CMDB as well as AWS account itself)

Target audience
Specify who this guide is intended for (e.g., beginners, advanced users, specific roles).

Categories
Proposed primary category and categories where this guide would fit best. (e.g., Getting Started, Best Practices, Troubleshooting, Concepts etc).

Outline
A brief outline of the main sections or topics the guide will cover.