investigate CKV_AWS_149 chekov warning suppression - in the affected workflows

[ewastempel]

User Story

Revisit fixing CKV_AWS_149 chekov warning that is currently suppressed.
See the workflows that were affected:
terraform-static-analysis.yml : https://github.com/ministryofjustice/modernisation-platform/actions/runs/5923065434/job/16058039084

Check: CKV_AWS_149: "Ensure that Secrets Manager secret is encrypted using KMS CMK"
	FAILED for resource: aws_secretsmanager_secret.rds_db_credentials
	File: /secrets.tf:19-22
	Guide: https://docs.paloaltonetworks.com/content/techdocs/en_US/prisma/prisma-cloud/prisma-cloud-code-security-policy-reference/aws-policies/aws-general-policies/ensure-that-secrets-manager-secret-is-encrypted-using-kms.html

		19 | resource "aws_secretsmanager_secret" "rds_db_credentials" {
		20 |   name                    = "tactical-products-db-secrets"
		21 |   recovery_window_in_days = 0
		22 | }

code-scanning.yml: https://github.com/ministryofjustice/modernisation-platform/actions/runs/5921047939/job/16053081949
Additionally add ticket to update all pipelines to use slack notifications when a pipeline fails.

if sensible then fix these.

Is it possible to use a custom KMS keys in this instance?

Value

Improving security posture.

Definition of done

• another team member has reviewed
• tests are green

Reference

How to write good user stories

[dms1981]

Applied KMS key to relevant resources, removed Checkov and Tfsec exclusions.