EE: Refactor Cluster services to enable groups or projects

What does this MR do?

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22181 + commit for EE override of can_create_cluster?

Refactor to allow group to be passed in a future MR for Cluster services when creating or updating clusters (Clusters::CreateService and Clusters::UpdateService)

These services currently require a project in the constructor by virtue of inheriting from ::BaseService, which should be changed to allow project (or group in the future

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/34758

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?