feat: Add NAT gateway interface ids output

[tormodmacleod]

Description

Added output of Network Interface IDs assigned to NAT Gateways

Motivation and Context

We send our flow logs to New Relic. This would save me having to use a data resource to get the network interface IDs as below

data "aws_nat_gateway" "nat_gateway" {
  for_each = toset(module.vpc.natgw_ids)

  id = each.value
}

Breaking Changes

No, there should be no backwards compatibility issues resulting from this change

How Has This Been Tested?

I tested this locally by changing the source of one of my projects which uses the vpc module

[github-actions]

This PR has been automatically marked as stale because it has been open 30 days
with no activity. Remove stale label or comment or this PR will be closed in 10 days

[antonbabenko]

This PR is included in version 5.3.0 🎉

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues. If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.