Docs: Add "Network Requirements" / Ports Reference Section

### Current Behavior

The documentation currently lacks a centralized reference for the network ports required to operate Dependency-Track.

Administrators attempting to configure firewalls, Kubernetes Network Policies, or AWS Security Groups currently have to derive port requirements by looking through Docker Compose files, source code, or individual integration pages. There is no single "Network Requirements" section that lists what incoming and outgoing ports must be open for a production deployment.

### Proposed Behavior

I propose adding a **"Network Requirements"** section to the "Getting Started" or "Configuration" documentation to clearly list these requirements.

Below is the draft content and I submit it via PR, but idk where exactly:

### Ingress (Incoming Traffic)
| Service | Container Port | Default Host Port | Protocol | Notes / Production Mapping |
| :--- | :--- | :--- | :--- | :--- |
| **Frontend** | `8080` | `8080` | HTTP | The web UI. In production, this can be exposed via a Reverse Proxy/Load Balancer on port **443** (HTTPS). |
| **API Server** | `8080` | `8081` | HTTP | The backend REST API. The frontend (browser) must be able to reach this. Often mapped to **443** via a proxy. |
| **Bundled** | `8080` | `8080` | HTTP | *(Legacy)* If using the bundled image, it handles both UI and API on a single port. |

> **Note:** The official Docker images run as non-root users and cannot bind to privileged ports (80/443) internally. You can map these to port 80/443 using Docker port mapping or a reverse proxy.

### Egress (Outgoing Traffic)
| Destination Type | Port | Description |
| :--- | :--- | :--- |
| **Database** | `5432` / `3306` / `1433` | **Required.** Connection to external database (`PostgreSQL` / `MySQL` / `MSSQL`). |
| **Vulnerability Sources** | `443` | **Required.** HTTPS connections to NVD, GitHub Advisories, OSS Index, Snyk, etc. |
| **Repo Meta Analysis** | `443` | **Required.** HTTPS connections to Maven Central, NPM, PyPi, etc. |
| **OIDC / LDAP** | `443` / `389` / `636` | **Optional.** Identity provider connections. |
| **Notifications** | `25` / `465` / `587` | **Optional.** SMTP for email notifications. |
| **Webhooks** | `80` / `443` | **Optional.** Notifications to Slack, Teams, or custom webhooks. |

### Checklist

- [x] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/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