Add vulnerable dependency list

What does this MR do?

This adds a second dependency list which only displays dependencies with vulnerabilities. The user is able to switch between the two lists via the associated tabs.

This contributes towards the larger feature for adding dependency scanning results to the Dependency List, behind the dependency_list_vulnerabilities feature flag.

This MR depends on gitlab-ui!623 (merged), though it is not blocked by it, since this MR's work lies behind a feature flag.

Feature flag disabled

Before this MR, feature flag enabled

After this MR, feature flag enabled

After this MR, feature flag enabled, after gitlab-ui!623 (merged) has been merged

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Style guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.