Document Support for Amazon Aurora PostgreSQL with the AWS JDBC Driver

### Problem Statement

Amazon Aurora PostgreSQL is one of the most widely adopted managed PostgreSQL services. Since Dependency-Track v5 supports only PostgreSQL, providing guidance for deploying with popular managed PostgreSQL offerings would improve the adoption and operational experience for many users.

When using Amazon Aurora PostgreSQL, the Amazon Web Services (AWS) JDBC Driver provides several capabilities beyond the standard PostgreSQL JDBC driver, including:

- Automatic connection failover when the writer instance changes in a Multi-AZ cluster.
- Support for IAM-based secure passwordless authentication.
- Additional Aurora-specific connection management and resiliency features.

Although support for the AWS JDBC Driver was previously introduced (#4303) , it was later removed, primarily due to the additional size of the dependency.

### Proposed Behavior

Rather than including the AWS JDBC Driver as a bundled dependency, document how users can install and configure it as an optional add-on when running Dependency-Track with Amazon Aurora PostgreSQL.

This approach strikes a good balance by:

- Keeping the default Dependency-Track distribution lightweight.
- Allowing users who deploy on Amazon Aurora PostgreSQL to benefit from the enhanced capabilities of the AWS JDBC Driver.
- Avoiding the maintenance and distribution overhead of shipping the driver with every release.

The documentation could include:

- Required AWS JDBC Driver JAR(s).
- How to add the driver to a Dependency-Track deployment.
- Required JDBC URL and driver configuration.
- Any additional considerations or known limitations.

**Reference :**

A similar approach is used by Keycloak, which documents how to prepare the server for Amazon Aurora PostgreSQL without bundling the AWS JDBC Driver by default. This could serve as a useful reference for the documentation approach.

https://www.keycloak.org/nightly/server/db#preparing-keycloak-for-amazon-aurora-postgresql

### Checklist

- [x] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/main/CONTRIBUTING.md#filing-issues)
- [x] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested

Start by locating Dependency-Track’s existing PostgreSQL deployment documentation and compare its structure with the linked Keycloak Aurora guidance. Document the required AWS JDBC Driver JARs, how to add them, the JDBC URL and driver settings, plus known limitations, without bundling the dependency by default. Done means an Aurora PostgreSQL user can follow the documentation to configure the optional driver.

Written by the indexing model from the issue text.