Feature Request: Use custom DB parameter group enhancement

[ferricoxide]

Problem Description:

It may be desirable to offer the ability to customize database tuning-options. Need the DB to use a custom — rather than the currently used RDS-default — parameter group.

Expected Behavior:

Ability to tune DB behavior via DB parameter-group settings

Actual Behavior:

Current use of RDS-default DB parameter-group precludes tuning customizations

(Detailed) Steps to reproduce:

Deploy RDS DB from existing templates

(Optional) Fix recommendation:

Add a AWS::RDS::DBParameterGroup resource-type into the current RDS templating.