Use RDS for production

[khandelwal]

Our current production instance doesn't use RDS - and uses a database running on an EC2 instance. Let's change it to use a production RDS.

• [x] Setup production RDS
• [x] Configure production openFOIA instance to use RDS.

[khandelwal]

There's a production RDS instance setup now, and openfoia is using it.

The production RDS instance is called: "openfoia-production-cf".