Adjust the vertical offset of the content to match our previous dropdown
menus, which looked better.

This provides more flexibility as it can be used to set color as well as
size and it is also more consistent with how everything else is styled in the
application.

Replace the existing use of the `size` prop and tweak menu item icon
sizes.

 - Add a clearer comment to explain what the global event listener
   effect is for
 - Add comment explaining what `ignoreNextClick` flag is for
 - Remove a test for the `ignoreNextClick` flag when a "click" event
   happens _outside_ of the menu toggle button. This _should_ close
   the menu
 - Use CSS classes to set menu alignment
 - Add some additional tests

The implementation is missing. It will be added in a follow-up PR.

`map` returned its argument but never called its callback!

Following design changes to the menus that will use this component, this
option is no longer needed.

Add new icons for the new menu component and the new groups menu. Also
add a `size` prop to the `SvgIcon` component so that icons can be sized
appropriately for usage in a given context.

Implement a new dropdown menu component that will replace all drop-down
menus in the sidebar and is also intended to be used in the LMS activity
views in future.

The menu consists of several components:

 - `Menu` is the dropdown menu itself, with a toggle button and menu
   content
 - `MenuSection` is a group of menu items with an optional heading
 - `MenuItem` is a menu item with a label, optional icon and optional
   submenu with additional actions. The submenu is going to be used for
   auxilliary links and actions related to groups in the groups menu

Upgrade node-sass and fsevents for Node v12 compatibility

Refactor groups service's `load` method

 - Capitalize "API" consistently
 - Remove a couple of comments that repeated the code below

Import fix for a warning caused by a "quietly" failing test.

As pointed out during code review, mixing the terms "selected" and
"direct-linked" to refer to direct-linked annotations and groups is
potentially confusing. Use the term direct-linked consistently.

Fix a silently failing test

The `HypothesisAppController#login()` method returns a Promise and calls
`fakeStore.clearGroups` asynchronously. This means we need to wait for
the result before checking the spy, and return the result in the test
case so Mocha knows when the test has finished.

Clarify what the method does and add some comments to explain to the
reader the high-level steps that it goes through.

The first block produced a result synchronously, so it could be combined
into the second block.

Rework the block that fetches the direct-linked annotation's group and
adds it to the featured groups list so that there is only one return
point at the end.

Remove unused babel-preset-env dependency

This has been superceded by @babel/preset-env

Fix direct linked private login flow

For easier debugging when tests fail, ensure that `it` cases that refer
to specific functions in a module are grouped under a `describe` block
labeled with the function's name.

Despite the name of the settings key where this value is read from
(`settings.annotations`), only a single annotation is currently
supported. See the `initialSelection` function in
`store/modules/selection.js`.

- Clear groups service state on login and logout.
- Handle case where focus group is null when watching the focused group
and userid for changes. This can happen when clearGroups is called since
it sets the focus group to null which triggers a call to the watch
function. There are two watch function that get triggered; one in
sidebar-content, the other in the group service.
- Clear direct-linked id states on clearSelection and when a new
focusedGroup is selected.

- Rename direct-linked-group store module to direct-linked so that it
may track the state of all direct-linked related items.
- Add directLinkedAnnotationsId and directLinkedGroupId to direct-linked
store module. This provides an official location to track/change the
state of the settings.annotations and settings.group rather than
modifying them directly.

Bump @octokit/rest from 16.25.2 to 16.25.4

Merge pull request #1118 from hypothesis/dependabot/npm_and_yarn/babel-plugin-mockable-imports-1.5.0

Bump babel-plugin-mockable-imports from 1.4.0 to 1.5.0

Bump katex from 0.10.1 to 0.10.2

Bump codecov from 3.3.0 to 3.4.0

Bump scroll-into-view from 1.9.6 to 1.9.7

Bump gulp from 4.0.1 to 4.0.2

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 16.25.2 to 16.25.4.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v16.25.2...v16.25.4)
Signed-off-by: dependabot[bot] <support@dependabot.com>