Use `detailed_status` for displaying CI status of a project

We are now caching the pipeline status for a project using the Pipeline#status. We should however start using Pipeline#detailed_status for that.

The detailed_status (based on Gitlab::Ci::Status::Core) can be different based on the current user.

I think we should be able to store everything we need to build a status-object from Pipeline into redis , and then have the Gitlab::Cache::CI::ProjectPipelineStatus initialize the status object.

That way we can start using the extended status objects throughout all the views.

Initial discussion about this in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10313#note_26680029