[BUG][Functional] Routes - pcx routes only allow targeting one subnet group, not entire vpc CIDR range

[Brian969]

Required Basic Info

• Accelerator Version: v1.3.5

Describe the bug

• pcx routes only allow targeting one subnet, not entire vpc CIDR range
• see example

Failure Info

• Not a failure, simply a feature gap

Steps To Reproduce

• use a sample config file, with a local workload account based VPC which is NOT TGW attached
• On a workload account named {account-name} on VPC named {vpcname}, add the following config

          "pcx": {
            "source": "operations",
            "source-vpc": "Central",
            "source-subnets": "App",
            "local-subnets": "App"
          } 

On that same VPC, add the following to the route table (i.e. {vpcname}VPC_Common):

                {
                  "destination": {
                    "account": "operations",
                    "vpc": "Central",
                    "subnet": "App"
                  },
                  "target": "pcx"
                }

Add the following to the CentralVPC_Common route table on the Central VPC, Central OU:

                {
                  "destination": {
                    "account": "{account-name}",
                    "vpc": "{vpcname}",
                    "subnet": "App"
                  },
                  "target": "pcx"
                }

• This works as expected, adding the route to the workload accounts App subnet CIDR's to the Central VPC
• but Central should be able to communicate with all subnets in the peered VPC
• subnet field is mandatory and removal causes SM to fail
• we also do not support adding multiple routes to the same pcx in the same route table

Expected behavior

• add ability to drop the subnet parameter (maintain it as optional parameter for existing customers)
• use the VPC CIDR range for route creation, rather than the subnets
• true for both ends of the connection

Additional context

• Customers need to join all workloads in App, Data, Management to the MAD

[fredbonin]

Fixed in this PR :

https://github.com/aws-samples/aws-secure-environment-accelerator/pull/877

[archikierstead]

Done