Add support for security group rule descriptions

[vamsirede]

AWS has added new feature that allows customers to add a short description to individual security group rules.

https://aws.amazon.com/about-aws/whats-new/2017/08/simplify-management-of-security-groups-with-security-group-rule-descriptions/

[barnesm999]

There is an open PR for this: #1587

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!