This reverts merge request !28545

This is a CSS effort only.

Fixes the padding of the buttons to be `8px 12px`
(including border) so that the button height is
32px.

Also adjusts the border width for all buttons when
the state is `hover`, `focus`, or `active to be 2px
thick instead of 1px thick. This is accomplished
through an inset box-shadow as not to increase
the size of the button.

Fixes some colors for primary and tertiary buttons.

Add changelog file

Hover, Active, and Focus states have different colors in design.
This fix brings those colors up to date.

Bootstrap removed white-space nowrap from buttons in v4.2.1,
causing at least one bug, so this commit re-adds that style
to all buttons

Added stylelint to static-analysis
Updated yarn dependencies
CSS Fixes and rule adoptions of stylelint
Added stylelint-scss
Deduplicated yarn.lock to clear dependencies

First round of advanced stylelint rules

Mainly Vendor prefix updates related to flex

Updates to more webkit specific vendor prefixes

Finished all vendor specific fixes

Moved now 4 rules to warning

Fixed the new scss lint problems

More stylelint adaptions after rebase

EE MR: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9001

**Why?**
Commit 75496059 accidentally changed line height for all small buttons.
This fixes that by introducing some `btn-xs` variables.

Continues the iteration on the project overview UI:

- moved star, fork and new clone button
(copy SSH/HTTPS URLs) to top right,
  made them smaller
- avatar is now larger (64px)
- 'Request access' is now a link instead
  of a button
- overview comes before the description +
  changed styling and added icons
- description font-size is now 16px (large-paragraph)
- quick links to files are moved downwards
  below the commit/pipeline info
- margins changed to group content into
  4 groups to clean up the interface
- visibility info reduced to icon-only and
  moved to the right of the title

Rename btn-new, btn-create and btn-save to btn-success

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

Remove jquery.scss; Combine multiple duplicate grays into global gray variables; Remove unused styles in common.scss

Closes #48182

Move html to haml file instead of JS