Add multi-region support for cases that don't rely only on a primary and secondary region

[diego-ojeda-binbash]

Describe the Feature

Currently the reference architecture supports a primary and secondary region which works for most cases. However, as clients scale up their businesses, they might face scenarios where they need to deploy their workloads to other regions, in order to address latency issues or to adhere to compliance requirements.
Such scenarios require a redesign of the reference architecture in order to support, at least, the following cases:

• Multi-region resource stacks
• Terraform state buckets in the same region as the resources they reference
• Automatic injection of the current region in order to remove hardcoded region definitions in the layers