i18n linting for .vue files under the
app/assets/javascripts/issue_show directory

Detect links containing zoom.us followed by j, s, or my
Add link below Issue title that links to Zoom meeting

This commit is the result of running `yarn eslint --fix` after enabling
the `no-implicit-coercion` ESLint rule.  This rule has been added to
our ESLint config here:

https://gitlab.com/gitlab-org/gitlab-eslint-config/merge_requests/14

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/13913

When editing an epic, the progress was previously lost due to
lack of localstorage syncing code. This commit adds support for
localstorage sync.

This MR rewrites existing Related Merge Requests widget
with Vue with reusing shared Related Issues components

Before, the styling for `img:not(.emoji)`` was repeated between
`.md:not(.use-csslab):not(.wiki)` (for comments and the Markdown
preview), `.documentation.wiki` (for help pages), and
`.issuable-details .description .wiki` (for MR and issue descriptions).

In these places, we now simply use `.md`. Wherever we use `.md` but
don't want this image styling (like wikis and blobs), `.md-file` is
added.

Also adds specs and fixes existing specs

This engine was replaced with CommonMarker in 11.4, it was deprecated
since then.