Implement slow connection indicator

bigbluebutton-html5/imports/api/users/server/methods.js

...pi/users/server/methods/setUserEffectiveConnectionType.js

...utton-html5/imports/api/users/server/modifiers/addUser.js

.../users/server/modifiers/setUserEffectiveConnectionType.js

bigbluebutton-html5/imports/ui/components/app/component.jsx

...ml5/imports/ui/components/notifications-bar/container.jsx

...html5/imports/ui/components/slow-connection/component.jsx

...r-participants/user-list-item/user-dropdown/component.jsx

...user-participants/user-list-item/user-icons/component.jsx

...t/user-participants/user-list-item/user-icons/styles.scss

bigbluebutton-html5/imports/ui/services/user/mapUser.js

bigbluebutton-html5/private/config/settings.yml

bigbluebutton-html5/private/locales/en.json