feat: multi-region deployment

[chris13524]

Description

Adds 2 more regions, us-east-1, and ap-southeast-1 to the deployment.

Remaining work:

• Refactor alerting & monitoring modules: they expected single instances of services before
• Gracefully migration of existing Terraform resources
  • Comment out new regions & just move the existing regions
  • Use moved to verify no resources are actually re-created: https://developer.hashicorp.com/terraform/tutorials/configuration-language/move-config
  • Uncomment other regions
• Create IRN VPC peering for other regions?
• DNS load balancing + certificates
• Only deploy Postgres in eu-central-1 region
  • Connect to eu-central-1 Postgres (VPC peering?)
• Test deployment in staging environment

Follow-up work:

• Consider making a unified dashboard for all regions (instead of or in addition to a dashboard for each)
• Consider Postgres read replicas

How Has This Been Tested?

Will be tested by manually deploying to staging environment.

Due Diligence

• Breaking change
• Requires a documentation update
• Requires a e2e/integration test update