This fixes the remainder of the GitPushService specs.

Closes #13663

Add the `read_build` ability if user is anonymous or guest and allow_guest_to_access_builds is enabled.

This MR simplifies CI permission model:
- read_build: allows to read a list of builds, artifacts and trace
- update_build: allows to cancel and retry builds
- create_build: allows to create builds from gitlab-ci.yml (not yet implemented)
- admin_build: allows to manage triggers, runners and variables
- read_commit_status: allows to read a list of commit statuses (including the overall of builds)
- create_commit_status: allows to create a new commit status using API

Remove all extra methods to manage permission.
Made all controllers to use explicitly the new permissions.

Also fix a few places where page_404 should be render_404.

It won't change anything after they are first invoke, so add method cache to avoid allocations and avoid GC.

Benchmarks:

```
Calculating -------------------------------------
project_guest_rules without method cache
                        79.352k i/100ms
project_guest_rules with method cache
                        93.634k i/100ms
-------------------------------------------------
project_guest_rules without method cache
                          2.865M (±32.5%) i/s -     11.982M
project_guest_rules with method cache
                          4.419M (± 7.4%) i/s -     22.004M

Comparison:
project_guest_rules with method cache:  4418908.0 i/s
project_guest_rules without method cache:  2864514.0 i/s - 1.54x slower

Calculating -------------------------------------
project_report_rules without method cache
                        53.126k i/100ms
project_report_rules with method cache
                        97.473k i/100ms
-------------------------------------------------
project_report_rules without method cache
                          1.093M (±36.5%) i/s -      4.675M
project_report_rules with method cache
                          4.420M (± 7.2%) i/s -     22.029M
Comparison:
project_report_rules with method cache:  4420054.3 i/s
project_report_rules without method cache:  1092509.6 i/s - 4.05x slower
```

https://gist.github.com/huacnlee/b04788ae6df42fe769e4

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

refactored code as projects only have one owner. Kept some refactoring in place (has_owners concern)

- Offloads uploading to GitLab Workhorse
- Use /authorize request for fast uploading
- Added backup recipes for artifacts
- Support download acceleration using X-Sendfile

refactored permissions and added update_project_member ability logic. Also refactored owner methods to a concern.

This was previously possible through the API but can now be done
through the project#edit settings screen if the current user is
the owner of the project.
Update changelog

This was necessary because this permission is checked dynamically by
`app/views/shared/issuable/_context` when on a Merge Request.

Closes #2058

Unauthenticated users had access to disabled features of public
projects. The code has been slightly refactored so that feature checks
are done in a separate method and can also be applied for public access.

The label page was added to navigation for unauthorized users because
the previously used milestone read permission was still checked. This
has been fixed and read access to labels is now granted (again) for
public projects.

This regression has been introduced in
07efb17e (7.12).

See also 9bcd3639.

Refs !836, !842.

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>