It's not supposed to go on top of everything, like an error would. It's tied to
a conference, so render it outside of the OverlayContainer.

Prepare for React 16.

- Create a notification component for displaying a toggle.
- Create an action for showing the component if allowed by
  the local storage setting and for saving the setting to
  local storage.
- Remove all notifications having a timeout by default so the
  device error notification must be dismissed manually.
- Split the camera and mic error dialog into two separate
  notifications.

* feat(notifications): implement a react/redux notification system

* squash into impl explicit timeout, style

* ref(notifications): convert toastr notifications to use react

* ref(toastr): remove library

* squash into conversion: pass timeout

* squash into clean remove from debian patch