Merge branch 'replace-jquery-cookie-plugin' into 'master'

Replace jquery-cookie plugin with js-cookie

## What does this MR do?

Removes an outdated and unmaintained dependency [jquery.cookie](https://github.com/carhartl/jquery-cookie) with its successor [js.cookie](https://github.com/js-cookie/js-cookie) which is not dependent on jQuery.

Also this MR adds a global default cookie `path` setting which defaults to the GitLab root directory.  Now, setting a cookie to any path other than `gon.relative_url_root` requires an explicit opt-out.  This is a sensible default and should prevent accidental omission going forward.

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

Double check that all instances of `$.cookie(x)` have been replaced by `Cookies.get(x)` and all instances of `$.cookie(x, y, z)` are replaced with `Cookies.set(x, y, z)`.  All javascripts which set or retrieve cookie values should function just as before.

## Why was this MR needed?

One more step toward shaking off jQuery as a dependency (#23022), also [jquery.cookie](https://github.com/carhartl/jquery-cookie) is no longer maintained and hasn't seen an update in 2+ years.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- Tests
  - [x] 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 it does - 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?

#23022

See merge request !7085

1 files changed, 5 insertions, 1 deletions

diff --git a/app/assets/javascripts/application.js b/app/assets/javascripts/application.js
index c6c3c82e1ee..879f90bdc05 100644
--- a/app/assets/javascripts/application.js
+++ b/app/assets/javascripts/application.js
@@ -11,13 +11,13 @@
 /*= require jquery-ui/effect-highlight */
 /*= require jquery-ui/sortable */
 /*= require jquery_ujs */
-/*= require jquery.cookie */
 /*= require jquery.endless-scroll */
 /*= require jquery.highlight */
 /*= require jquery.waitforimages */
 /*= require jquery.atwho */
 /*= require jquery.scrollTo */
 /*= require jquery.turbolinks */
+/*= require js.cookie */
 /*= require turbolinks */
 /*= require autosave */
 /*= require bootstrap/affix */
@@ -145,6 +145,10 @@
     $document = $(document);
     $window = $(window);
     $body = $('body');
+
+    // Set the default path for all cookies to GitLab's root directory
+    Cookies.defaults.path = gon.relative_url_root || '/';
+
     gl.utils.preventDisabledButtons();
     bootstrapBreakpoint = bp.getBreakpointSize();
     $(".nav-sidebar").niceScroll({