Feature: JDBC driver for postgresql

When using AWS, it is possible to use the [AWS JDBC Driver for PostgreSQL](https://awslabs.github.io/aws-postgresql-jdbc/) which significantly simplifies connecting to a database from an application using IAM authentication.

It would be amazing to have something similar within azure, such that I can specify the driver and any parameters within the JDBC connection string to empower database access.

Generally, I connect as the admin within migration scripts to configure additional roles and permissions within the database. Connecting as the additional roles which map to workload-indentities within AKS is slightly painful currently as the application needs to be aware of the PostgreSQL endpoint of Azure such that it can:

- create an access token from the given identity-token
- refresh the token before it expires (ensures any new connections being opened within the long-running app work)

Having the ability to abstract this logic into a driver feels right, as the application is unaware of the implementation details around authentication to PostgreSQL besides a driver.