Require Configuration or Generation of a Strong, Temporary Initial Administrator Password

### Current Behavior

**Problem:**
The default administrator username and password ("admin"/"admin") for a new Dependency-Track instance are widely known. This presents a critical security vulnerability immediately after deployment, leaving new systems exposed until the password is manually changed.

**Context:**
Mandating the configuration or generation of a strong, temporary initial password is crucial for the security of new Dependency-Track deployments. This eliminates the immediate and significant risk associated with the well-known default credentials and ensures that all new instances start with a more secure footing, while still enforcing a password change upon first login.

### Proposed Behavior

**Solution:**
Implement a mandatory mechanism to avoid the use of default credentials. This could be achieved by **requiring** one of the following:

1. **Configuration-based Initial Password:** Administrators must define a strong, temporary initial administrator password via configuration (e.g., an environment variable) prior to the first startup.
2. **Automatic Password Generation:** If no initial password is provided via configuration, the application should automatically generate a strong, temporary initial password upon the first startup and log it securely.

In either case, the system should **require** the administrator to change this temporary password upon their first login.

**Alternatives Considered:**
The current approach relies on administrators manually updating the default password post-deployment, which leaves a significant window of vulnerability.

### 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