Added subnav to all views bar issuable views
## What does this MR do?
Adds subnav to all views apart from issue and MR views. The full list is available in screenshots below.
It also adds some JS to the builds page to simply handle the repositioning of the fixed position sidebar with the addition of the subnav.
## Are there points in the code the reviewer needs to double check?
## Why was this MR needed?
~UX and apparently ~regression .
## What are the relevant issue numbers?
Closes#18844.
## Screenshots (if relevant)
### Label
#### Edit
#### New
### Milestone
#### Edit
#### New
#### Show
### Commit
#### Show
#### Builds
### Blob
#### Blame
#### Edit
### Pipelines
#### Show
#### Show build
#### Edit Envrionment
## Does this MR meet the acceptance criteria?
- [ ] [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
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)
Closes#18844
See merge request !5998
2ebc63dd3c