Add hints to file upload vulnerability

[preetkaran20]

Problem statement
If you look at VulnerableApp-facade which is the User-interface for VulnerableApp-php, it has a way to tell the hints so that users can learn about the Vulnerability.

Solution
So we need to expose that hints objects, have a look at: https://github.com/SasanLabs/VulnerableApp-php/blob/main/src/FileUploadVulnerability/FileUpload.php#L428 for exposing hint metrics. Hints is present in the object definition:

VulnerableApp-php/src/FacadeSchema/VulnerabilityLevelDefinition.php

Line 10 in f804605

private $hints = [];

, we need to populate it.