WIP: Add create issue button on alert details page - Part 1

What does this MR do?

Adds create issue button on alert details page which links to an empty issue page

❗ As suggested in this comment we're splitting issue creation from alerts details page into 3 parts (FE wise)

PARTS:

✅ Current MR - Button behind feature flag linking to empty issue page

✅ Second MR to prefill text using URL query params

❌ Third MR to automatically create issue when you click the button (with BE support)

Feature flags

🇺🇦 ALert details page is behind feature flag alert_management_detail.

Button itself has dedicated FE feature flag create_issue_from_alert_enabled

Screenshots

⚠ this page has basic layout, so it might look like broken on the screenshot but it is just not ready yet

## Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry since behind 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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

References #213909 (closed)