Organize more the templates according to the software approach DDD

[abdennour]

Anything related to network and templates/vpc.fcn.yml can be combined in a single template named network.yml.

The network template should include:

• Parameters as: health check Ports, Bashion SSH Port (Best practice to not use 22), DB Ports.
• Resources as:
  • VPC resources: Routers, Subnets,... (which are now provisioned within templates/vpc.fcn.yml)
  • AWS::RDS::DBSubnetGroup: which now provisioned within templates/db.cfn.yml.
  • LoadBalancer: namely if it is a shared ALB among multiple target groups.
• Outputs: So other templates can refer to the network resources seamlessly (ImportValue+ Export or nested stacks).

I would suggest the same for monitoring, All SNS topics should be in the monitoring template.