New Check: Amazon Relational Database Service (RDS) Reserved Instance Optimization

[brittandeyoung]

Summary

Checks your usage of RDS and provides recommendations on purchase of Reserved Instances to help reduce costs incurred from using RDS On-Demand.

Motivation

Reservations can provide savings over on-demand pricing.

Additional context

https://docs.aws.amazon.com/awssupport/latest/user/cost-optimization-checks.html#amazon-rds-reserved-instance-optimization