Add option to enable Jira issue creation from vulnerabilities

What does this MR do?

It adds settings to the Jira-integration page, which allows to toggle using Jira for the creation of vulnerability-related issues.

Screenshots (strongly suggested)

Screenrecording

jira-vulnerabilities-options

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry (Behind default-disabled feature flag)
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Related to #289810 (closed)