Add CloudWatch logging to RDS instance

[BrianEllwood]

Pull Request Objective

This piece of work is being tracked in this GitHub Issue.

While investigating issue 3193 we could not look at the metrics in CloudWatch as the metrics were only available for a short period, I have since found that this information is available via the RDS console for 15 months. Unfortunately the RDS error logs are only retained for 3 days, which is the default. We could increase the rds.log_retention_period but thais could cause issues with spaces on the RDS instance and has a maximum of 7 days which would not have helped the previous investigation.

This piece of work is so we can store our PostgreSQL log records in Amazon CloudWatch Logs

Checklist

• I have reviewed the style guide and ensured that my code complies with it
• All checks have passed (or override label applied, if I've used the override-static-analysis label, I've explained why)
• I have self-reviewed my code
• I have reviewed the checks and can attest they're as expected

Additional Comments

Can the reviewer please confirm that this is an appropriate approach to resolving this issue

[github-actions]

Terraform Component 🧱: aws-analytical-platform-development-cluster

Checkov 🛂: failure

Trivy 🛂: failure

Static Analysis Override Label 🏷️: false

Pusher: @BrianEllwood, Action: pull_request, Working Directory: terraform/aws/analytical-platform-development/cluster, Workflow: Terraform, Marker: aws-analytical-platform-development-cluster_static_analysis

[github-actions]

Terraform Component 🧱: aws-analytical-platform-development-cluster

Terraform Initialization ⚙️: success

Terraform Validation 🤖: success

Terraform Plan 🛠️: success

Pusher: @BrianEllwood, Action: pull_request, Working Directory: terraform/aws/analytical-platform-development/cluster, Workflow: Terraform, Marker: aws-analytical-platform-development-cluster_plan