* Add missing `Fn::GetAtt` attributes to S3 bucket mock
Addresses an issue reported here https://github.com/localstack/aws-cdk-local/issues/1
* Reformat touched files with `black`
* Reformat touched files with `black` on Python 3.7
* IAM User Cloudformation Enhancements: update, delete, getatt.
* AWS::IAM::Policy Support
* Added unit tests for AWS:IAM:Policy for roles and groups. Fixed bug related to groups.
* AWS:IAM:AccessKey CloudFormation support.
* Refactor of CloudFormation parsing.py methods to simplify and standardize how they call to the models. Adjusted some models accordingly.
* Further model CloudFormation support changes to align with revised CloudFormation logic. Mostly avoidance of getting resoure name from properties.
* Support for Kinesis Stream RetentionPeriodHours param.
* Kinesis Stream Cloudformation Tag Support.
* Added omitted 'region' param to boto3.client() calls in new tests.
Co-authored-by: Joseph Weitekamp <jweite@amazon.com>
