Add support for k8s cluster applications - Helm tiller installation

What does this MR do?

WIP

FE from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15064

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

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated (This will be fixed in follow-up MR)
• [-] API support added (Today we don't support API yet)
• 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?

#38464 (closed) #36629 (closed)