Add license compliance to security configuration page

What does this MR do?

This MR adds the license compliance feature to the security configuration page.

• Refactors Security::JobsFinder into an abstract class
• Adds Security::SecurityJobsFinder < Security::JobsFinder for fetching security jobs that find vulnerabilities
• Adds Security::LicenseManagementJobsFinder for fetching license compliance jobs

Fixes part of #13638 (closed)

• Changelog entry covered in upcoming MR that releases feature
• Documentation created/updated covered in upcoming MR that releases feature
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content