Add Ingress to cluster applications section

What does this MR do?

• Add Ingress to cluster applications section

Follow up to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15064

Created so @ayufan has the FE necessary if we do actually ship Ingress in %10.2

.	Mobile

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/35958

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cc @ayufan