Add dependency paths data to vulnerabilities

What does this MR do and why?

Add dependency paths data to vulnerabilities

Adds dependency paths data to vulnerabilities model. Also adds DependencyPathsFinder, which for now just calls the find method on the model

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Go to any project with vulnerable packages
2. Go to Dependency List and select a vulnerable package (given, the ancestors array is not empty for the occurrence)
3. From the dropdown go to its vulnerability
4. In the controller response you should see dependency_paths available

Relates to: #520763 (closed)