Add CVSS Vector to CSV

What does this MR do and why?

Add CVSS Vector to CSV

1. Add CVSS Vector to vulnerability export CSV
2. Fixes CVSS parsing to vulnerability table.
3. Update document list with the new field.

Changelog: added EE: true

Screenshots or screen recordings

How to set up and validate locally

1. Run the dependency scanning job.
2. Check the report has cvss_vector field.
3. Check that the vulnerability.cvss field is populated in db via rails console.
4. Go to security > vulnerability report page and export csv.
5. CSV should have CVSS Vectors column with values.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #422034 (closed) and CVSS field of Vulnerability is not parsed (#431402 - closed)