Improve design of Pipeline view
## What does this MR do?
Improves current design of Pipelines view when there is multiple stages.
This makes the statuses clickable and makes the view more compact.
## Screenshots (if relevant)
cc @DouweM @markpundsack @rspeicher @marin
See merge request !4230
- Remove unused Gitlab::Application.routes.url_helpers from Ci::Build
- Remove too much logic from a view, use Ci::Commit.matrix_builds
- Use ci_status_with_icon
- Don't describe symbols
- Remove all view related methods from Ci::Build and CommitStatus
- Remove unused Ci::Commit and Ci::Build methods
- Use polymorphism to render different types of CommitStatus
