Epic Template descriptions and documentation.

<--- NOTE: this Epic need an initial spike to evaluate:

• options to support it in hybrid mode (does AWS provides an API to show supported features [NAT GW] in the Local Zone, or just a landing page?)
• if does not have API, will we need to keep a static list in installer with supported zones, and provide one field to force include it?
• Will the logic became complex (terraform mapping, etc)?

--->

Epic Goal

• (evaluate the) Support NAT Gateways in AWS Local Zones

AWS Announcement: https://aws.amazon.com/about-aws/whats-new/2023/07/aws-local-zone-phoenix-arizona/ 

AWS Annoucement blog: https://aws.amazon.com/blogs/aws/new-aws-local-zone-in-phoenix-arizona-more-instance-types-more-ebs-storage-classes-and-more-services/

Why is this important?

• AWS Local Zones feature was created in installer without support of AWS NAT Gateways, due AWS Limitation, but recently AWS announced the support of it in one zone, with promises of increase the coverage soon.

Scenarios

1. As a customer, I would like to keep my worker the private subnets in Local Zones egressing the traffic from that zone, instead in the parent zone in Region, so I can decrease the charges of the outbound traffic crossing the zone (but it could increase the allocated costs [tradeoffs?])

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents.
• ...

Dependencies (internal and external)

1. ...

Previous Work (Optional):

1. AWS Local Zones Phase II (Full IPI): SPLAT-657

Open questions::

1. …

Done Checklist

• CI - CI is running, tests are automated and merged.
• Release Enablement <link to Feature Enablement Presentation>
• DEV - Upstream code and tests merged: <link to meaningful PR or GitHub Issue>
• DEV - Upstream documentation merged: <link to meaningful PR or GitHub Issue>
• DEV - Downstream build attached to advisory: <link to errata>
• QE - Test plans in Polarion: <link or reference to Polarion>
• QE - Automated tests merged: <link or reference to automated tests>
• DOC - Downstream documentation merged: <link to meaningful PR>