Merge branch '21764-build-page-title' into 'master'

Remove project_title additions from builds and environments

## What does this MR do?

Removed soon-to-be un-needed project title additions from builds and environments.

**This MR depends on !5998, which introduces subnav to these pages. Without it we're just removing a useful link.**

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

@iamphill Is this right of me? One of these still exists in `projects/artifacts/browse`, I'm not sure whether to fix the issue with `project_title`, which already has some issues with its chevron, or just remove it as it will soon be redundant.

## Why was this MR needed?

## Screenshots (if relevant)

**BEFORE:**

![Screen_Shot_2016-10-27_at_14.58.22](/uploads/2915289fb06603c33d1abbcdab70c962/Screen_Shot_2016-10-27_at_14.58.22.png)

**AFTER:**

![Screen_Shot_2016-10-27_at_14.58.29](/uploads/ad8574aeaa6771737bb9002d749b5559/Screen_Shot_2016-10-27_at_14.58.29.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21764

See merge request !6160