feat(notifs): add notifications in tabs

app/i18n/en.i18n.json

app/i18n/fr.i18n.json

app/imports/api/notifications/methods.js

app/imports/api/notifications/server/publications.js

app/imports/ui/components/menus/MenuBar.jsx

app/imports/ui/components/menus/TopBar.jsx

...orts/ui/components/notifications/NotificationsDisplay.jsx

...i/components/notifications/TabbedNotificationsDisplay.jsx

app/imports/ui/components/notifications/styles.js

app/imports/ui/components/users/AdminSendNotification.jsx

app/imports/ui/layouts/MainLayout.jsx

config/README.md

config/settings.development.json.sample