Add CloudFormation support for create-public-ipv4-pool and provision-public-ipv4-pool-cidr for Public IPAM BYOIP provisioning

### Name of the resource

Other

### Resource name

AWS::EC2::CreatePublicIpv4Pool, AWS::EC2::ProvisionPublicIpv4PoolCidr

### Description

As demonstrated on [Steps 8 and 9](https://docs.aws.amazon.com/vpc/latest/ipam/tutorials-byoip-ipam-ipv4.html#tutorials-byoip-ipam-ipv4-9) of using Public IPv4 BYOIP, the two functions listed above are available only via AWS CLI / SDKs at the moment, and not through CloudFormation.

This impose significant challenges on how far our automation can go to provision new VPCs with slices of public BYOIP IPAM pools.

We need to manage them through Cloudformation, especially when dealing with ephemeral VPCs.
With the help of Cloudformation lifecycle, when the user deletes the stack, CF should deprovision all IPv4s and delete the public ipv4 pool.

Start with the AWS Public IPv4 BYOIP tutorial linked in the issue, especially Steps 8 and 9, and review the requested AWS::EC2::CreatePublicIpv4Pool and AWS::EC2::ProvisionPublicIpv4PoolCidr resources. Done means CloudFormation coverage exists for both operations and stack deletion handles the requested IPv4 deprovisioning and public IPv4 pool cleanup.

Written by the indexing model from the issue text.