* Add integration test suite for ec2_vpc_subnet
* wrap boto3 connection in try/except
update module documentation and add RETURN docs
add IPv6 support to VPC subnet module
rename ipv6cidr to ipv6_cidr, use required_if for parameter testing, update some failure messages to be more descriptive
DryRun mode was removed from this function a while ago but exception handling was still checking for it, removed
add wait and timeout for subnet creation process
fixup the ipv6 cidr disassociation logic a bit per review
update RETURN values per review
added module parameter check
removed DryRun parameter from boto3 call since it would always be false here
fix subnet wait loop
add a purge_tags parameter, fix the ensure_tags function, update to use compare_aws_tags func
fix tags type error per review
remove **kwargs use in create_subnet function per review
* rebased on #31870, fixed merge conflicts, and updated error messages
* fixes to pass tests
* add test for failure on invalid ipv6 block and update tags test for purge_tags=true function
* fix pylint issue
* fix exception handling error when run with python3
* add ipv6 tests and fix module code
* Add permissions to hacking/aws_config/testing_policies/ec2-policy.json for adding IPv6 cidr blocks to VPC and subnets
* fix type in tests and update assert conditional to check entire returned value
* add AWS_SESSION_TOKEN into environment for aws cli commands to work in CI
* remove key and value options from call to boto3_tag_list_to_ansible_dict
* remove wait loop and use boto3 EC2 waiter
* remove unused register: result vars
* revert az argument default value to original setting default=None
* Allow backoff for describe_subnets
Improve exception handling to latest standards
* Add integration test suite for ec2_vpc_subnet
* Add test for creating subnet without AZ
Fix bug identified by test
Fixes#31905
