feat: Add Global Database support

[fatbasstard]

This PR adds support for Aurora Global Database.

Introduced 2 new variables to support the creation of a "Global Database":

• global_database_primary (bool): If specified a "global database cluster" is created and the cluster is added to it.
• global_database_secondary (object): If specified, the cluster is added to the Global Database (using the global_cluster_identifier which can be fetched from the outputs of the primary (only the primary)).

Variable validation is added to ensure/handle some requirements and limitations.

Some notable other changes:

• Refactored the mcaf-role module (used for Enhanced Monitoring) to use the Terraform Registry

Example:
The following setup is created with this module during development:

Documentation and Links:

• https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/aurora-global-database.html
• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/rds_global_cluster

[github-actions]

Terraform Format and Style 🖌success

Terraform Initialization ⚙️``

Terraform Lint 📖success

Terraform Validation 🤖success

Validation Output

Warning: Argument is deprecated

  with module.vpc.aws_eip.nat,
  on .terraform/modules/vpc/main.tf line 1044, in resource "aws_eip" "nat":
1044:   vpc = true

use domain attribute instead
Success! The configuration is valid, but there were some validation warnings
as shown above.