[Task]: Add AWS Security Hub to Terraform

[acouch]

Summary

AWS Security Hub provides continuous monitoring for NIST security controls.

This has been added to our account. This ticket is to export the settings to Terraform.

Acceptance criteria

• [ ] AWS Security Hub configs in Terraform

[coilysiren]

This can be done with resource imports, at minimum here's the account:

https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/securityhub_account

resource "aws_securityhub_account" "account" {}

$ terraform import aws_securityhub_account.account AWS_ACCOUNT_ID

The go through the other terraform resources and import them as well, as needed.

[jamesbursa]

We can disable controls that are false positives (e.g. not applicable to the system or implemented in a way that Security Hub can't detect) using resource "securityhub_standards_control" with the disabled_reason argument.

Example of use: https://github.com/ministryofjustice/modernisation-platform-terraform-baselines/blob/95eb114b7e11ea505061d03232cdd31857b1cd27/modules/securityhub/main.tf#L22-L29