feat: apigee NAT address resource

[modular-magician]

fixes hashicorp/terraform-provider-google#11804

Adding Apigee NAT Resource.

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Release Note Template for Downstream PRs (will be copied)

Apigee: Added Apigee NAT address resource `google_apigee_nat_address`

Derived from GoogleCloudPlatform/magic-modules#6475