If a value is not set in localStorage then null is
returned. null should not be converted to an empty
string (via _.escape) because that will then be
stored in localStorage as the user set preference
and will keep overriding any other values set
in localStorage for the displayname.

They may contain sensitive information.

VideoLayout schedules a large video update by passing in
the video stream on the small video instance. When a stream
is removed, the UI is removed from the small video instance
but a reference to the stream is left. So when VideoLayout
schedules the large video update after a stream removal,
the old stream from the small video instance is re-used,
even though it has been removed.

This change also brings balance with RemoteVideo method
"addRemoteStreamElement" which sets the stream on the
small video instance, so now "removeRemoteStreamElement
unsets it.

- Use actions to notify the rest of the app that
  a mic or camera error has occurred
- Use middleware to respond to those notifications
  of errors by showing in-app notifications and
  notifying the external api

This reverts commit f42d0411b1.

The UX provided by this feature flag in its current state is not
desired. Also, I noticed filmstrip sometimes failing to properly
update small video display mode on pin/unpin. The feature is
being left in for consumers of jitsi-meet to enable as needed.

When in a conference, try to enter PiP when pressing the back button. If this is
not possible (because it's unsupported, not enabled, etc.) fall back to the
previous behavior of simply hanging up.

This PR changes the logic for connecting / disconnecting conferences. Instead of
doing it in mount / unmount events from the Conference component, it moves the
logic to the appNavigatee action.

This fixes a regression introduced in 774c5ecd when trying to make sure the
conference terminated event is always sent.

By moving the logic to appNavigate we no longer depend on side-effects for
connecting / disconnecting, and the code should be more maintainable moving
forward.

An improvement to this is the concept of sessions, which, while not tackled
here, was taken into consideration.

People run these in their own checkout and will run into problems because
tagging will fail.

This reverts commit 603d161788.

Inverts the icons to follow more what's in the phone app instead of
CallKit.

* Groups devices notifications by type audio/video.

* Fixes passing correct device array.

The naming didn't match, so adjust it. @ cannot be used for maven artifact
names.