Redesign user settings UI

[jschwartzentruber]

Context:

The current user settings UI lists each tool as a checkbox. It would be nice to have a more responsive design that allows us to select tools and add these to a list of current subscribed tools. In production we have about 200 tools, so the UX is a wall of checkboxes.

The same should be applied to notification settings. Notifications only have a handful of options, but should use the same multi-select component for consistency and scalability.

Requirements:

User settings UI uses a responsive design for tool filter and notifications. This could be a drop-down adding to a set of x-able pill buttons representing the current list (eg. vue-multiselect) or something similar.

Acceptance Criteria:

Tool filter and notification settings are easily edited even with hundreds of options.

[gitstart-connector]

Issue synced into GitStart. Please review, edit and hand it off to GitStart by following this link.

[gitstart-connector]

This issue has been handed off to GitStart: https://clients.gitstart.com/mozilla/12016/tickets/FUZ-11

[jschwartzentruber]

Fixed in #15