Update "Using AWS Systems Manager Parameter Store for Configuration"

Small updates to the guide to bring it up to date, and add more samples:

- Switch to new modular PowerShell tools
- Add sample code to show use of the GetParametersByPath api

Locate the guide titled “Using AWS Systems Manager Parameter Store for Configuration” and review its current PowerShell tooling and configuration examples. Update it for the new modular PowerShell tools and add a GetParametersByPath API sample; the guide is done when both requested updates are present and consistent with the current AWS instructions.

Written by the indexing model from the issue text.