Enforce sslmode=require for Postgres database

[rafidka]

Overview

When crafting the connection string for connecting to the Postgres database, we currently pass sslmode=prefer. We need to make sure we always require sslmode.

Acceptance Criteria

• Do the necessary changes to allow always set sslmode=require to true.
• This should work Amazon MWAA. For Docker Compose, since we don't have SSL enabled for the Postgres service, then we cannot use require, but that's fine since it won't be used for production purposes.

[jessefrn1]

For Docker Compose, we don't have SSL enabled for the Postgres service.