This changes the pagination of the "Explore" pages so they use a simpler
pagination system that only shows "Prev" and "Next" buttons. This
removes the need for getting the total number of rows to display, a
process that can easily take up to 2 seconds when browsing through a
large list of projects.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/27390

GDK pipeline is failing with this error:
```
Downloading rubocop-rspec-1.15.1 revealed dependencies not in the API or the
lockfile (rubocop (>= 0.42.0)).
Either installing with `--full-index` or running `bundle update rubocop-rspec`
should fix the problem.
```
Updated lockfile by running the bundle update.

`gdk install` works now.

Closes gitaly#443

Closes gitaly#437

Closes gitaly#433

Closes gitaly#421

Closes gitaly#415

Closes gitaly#411

the rugged versions up to 0.26.0b3 had a bug concerning the signature
extraction. The extracted signature was not always the same, probably
due to a buffer (overflow) issue in libgit.

see https://github.com/libgit2/rugged/issues/608

unicorn forking new workers.

And this has already been done on EE, so it’ll match now.

Most notably, the net-ldap gem.

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

bump prometheus gem version

Closes gitaly#396

New version of the gem returns 200 status code on delete with content
instead of 204 so we explicitly set status code to keep existing
behavior
Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

24570 use re2 for user supplied regexp 9 3

See merge request !2129

This introduces JSON logging for Rails views saved to a file called
`development_json.log`, `production_json.log`, etc.

For example, instead of this unparsable log:

```
Started GET "/" for 127.0.0.1 at 2012-03-10 14:28:14 +0100
Processing by HomeController#index as HTML
  Rendered text template within layouts/application (0.0ms)
  Rendered layouts/_assets.html.erb (2.0ms)
  Rendered layouts/_top.html.erb (2.6ms)
  Rendered layouts/_about.html.erb (0.3ms)
  Rendered layouts/_google_analytics.html.erb (0.4ms)
Completed 200 OK in 79ms (Views: 78.8ms | ActiveRecord: 0.0ms)
```

We get a single line with this:

```
{"method":"GET","path":"/,"format":"html","controller":"HomeController","action":"index","status":200,"duration":79,"view":78.8,"db":0.0,"location":"http://localhost/","time":"2017-07-18 09:35:17 -0700"}
```

Part of #20060

Signed-off-by: NRémy Coutable <remy@rymai.me>

This reverts merge request !12753