This removes other outdated babel@6 dependencies as well.

Unfortunately the newer version of vue-jest has a dependency of an older
version of ts-jest. In order to satisfy the peerDependency from ts-jest,
we are forcing the version@24. The only "breaking" change from ts-jest
23->24 is that it requires a newer version of jest. This might be
obsolete soon, as vue-jest plans on switching to babel eventually.

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

Use gitlab-svg to provide the icons for rails, spring and express. For
the new GitLab pages templates, we are falling back to the GitLab logo.

- Use JS regex for emoji validation
- Add test for blocking emojis in full name
- Fix existing tests for user status that failed locally

v2.1.0 was published wrongly by the package author.

The schema is built on top of the default schema and Node and Mark
classes provided by tiptap-extensions. prosemirror-model is used to
parse HTML/DOM into a prosemirror document, and prosemirror-markdown is
used to serialize this document to (GitLab Flavored) Markdown.

https://babeljs.io/blog/2019/01/21/7.3.0

It seems like every new version of Chrome renders the favicon canvas
differently. This reduces the problems with it by creating a more fault
tolerant check, which compares the color values in the pixels and is
okay if they are within a certain threshold.

Upgrades prettier to 1.15.3
Runs `yarn prettier-save-all` against the codebase
Most changes are due to https://github.com/prettier/prettier/pull/5519

This reverts to 2.2.0, which has node@6 compatibility

This upgrades the following packages:
- Vue
- Vue Loader
- Vue Resource
- Vue Router
- Vue template compiler
- Vue Jest

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/53779