AWS::WAF::RateBasedRule

### Description
Add support for **AWS::WAF::RateBasedRule**

Problem:
As of now, we can create rate-based rules using a CloudFormation template. However we cannot add rate-based rules to a web ACL via cloudformation.
To add add rate-based rules to a web ACL we need to use AWS WAF console, API, or command line interface (CLI)

Expected behavior:
**AWS::WAF::RateBasedRule** resource will help creating RateBasedRule and adding it to WAF webACL via cloudformation.

Start by reviewing how this repository tracks CloudFormation coverage for AWS WAF resources and how AWS::WAF::RateBasedRule is represented by the CloudFormation and WAF APIs. Done means CloudFormation can create the rate-based rule and associate it with a WAF web ACL, with the repository's expected coverage documented or tested.

Written by the indexing model from the issue text.