Fix OmniAuth OAuth2Generic strategy not loading

Closes #62216

See merge request gitlab-org/gitlab-ce!28680

Internationalisation of lib directory

See merge request gitlab-org/gitlab-ce!27711

This is one of many MRs opened in order to improve the overall
internationalisation of the GitLab codebase.

i18n documentation
https://docs.gitlab.com/ee/development/i18n/externalization.html

Add "utility-first" section to FE scss style guide

Closes gitlab-ui#38

See merge request gitlab-org/gitlab-ce!28312

Fixes issue height of detail-page-header

Closes #62193 and #62107

See merge request gitlab-org/gitlab-ce!28650

detail-page-header-body class was making the height of the header 1 pixel too big to fit evenly

In https://github.com/rails/rails/commit/83b767ce, Rails 5.1 removed
support for using a String to specify a middleware. When the
strategy_class argument is passed from the GitLab YAML config to Devise,
Devise passes the string value straight through to Rails, and GitLab
would crash with a NoMethodError inside ActionDispatch::MiddlewareStack.

To make this OmniAuth strategy work again, we normalize the arguments by
converting the strategy_class value into an actual Class.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/62216

Improve doc based on Zeff's suggestions

See merge request gitlab-org/gitlab-ce!28664

Ignore files in tmp/rubocop_cache/**

See merge request gitlab-org/gitlab-ce!28672

Create a unified script to run Jest & Karma tests

Closes #58869

See merge request gitlab-org/gitlab-ce!27239

Edit CI/CD settings for SSOT guidelines

See merge request gitlab-org/gitlab-ce!28582

This commit ignores the temporary cache directories that I _think_ are
created by the VSCode Ruby extension.

Edit email settings for SSOT

See merge request gitlab-org/gitlab-ce!28629

Edit external auth for SSOT

See merge request gitlab-org/gitlab-ce!28630

API: Allow to get and set "masked" attribute for variables

Closes #61754

See merge request gitlab-org/gitlab-ce!28381

Container Registry is now proper cased

See merge request gitlab-org/gitlab-ce!28660

Update dependency @gitlab/svgs to ^1.62.0

See merge request gitlab-org/gitlab-ce!28605

Add new favicon for canary from next.gitlab.com

Closes #59026

See merge request gitlab-org/gitlab-ce!28601

Group download buttons in a .btn-group

Closes #61880

See merge request gitlab-org/gitlab-ce!28599

The suggestions were made while we were pair programming.

Fix issue importing members with owner access

Closes #61715

See merge request gitlab-org/gitlab-ce!28636

Add changelog
Added wrong favicon

Add note for index requirement with FK constraint in migration_style_guide.md

See merge request gitlab-org/gitlab-ce!28003

Update migration_style_guide.md

Reduce height of issue board input to align with buttons

Closes #49041

See merge request gitlab-org/gitlab-ce!28604

Update new smiley icons

Closes #62054

See merge request gitlab-org/gitlab-ce!28338

Add new emoji icons
Remove added SVGs
Change to sprite_icons
Prettify
Fix text left behind
Fix errors
Remove background top level reaction icon

Change system notes to use relative urls

Closes #55441

See merge request gitlab-org/gitlab-ce!28588

Stage labels are now scoped

See merge request gitlab-org/gitlab-ce!28652

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