This refactors all handling of audio-only and last N to 2 features in preparation
for "low bandwidth mode".

The main motivation to do this is that lastN is a "global" setting so it helps
to have all processing for it in a single place.

* Listens for suspend events from jitsi-power-monitor on postis channel.

* Removes duplicated type and actions.

* Moves suspendDetected state from overlay to power-monitor feature.

The functionality around logging including logging_config.js i.e.
loggingConfig and the other classes and/or functions that initialize
loggers for Jits Meet truly deserves a feature of its own. Start getting
in that direction on both Web and mobile by introducing
features/base/logging and bringing loggingConfig to mobile.

The Device Selection modal consists of:
- DeviceSelection, an overly smart component responsible for
  triggering stream creation and cleanup.
- DeviceSelector for selector elements.
- VideoInputPreview for displaying a video preview.
- AudioInputPreview for displaying a volume meter.
- AudioOutputPreview for a test sound output link.

Store changes include is primarily storing the list of
available devices in redux. Other app state has been left
alone for future refactoring.

On Android the status and navigation bars are shown again after coming back from
the background, so enter full-screen mode again if needed.

The implementation varies across platforms, with the same goal: allow the app to
use the entire screen real state while in a conference.

On Android we use immersive mode, which  will hide the status and navigation bars.

https://developer.android.com/training/system-ui/immersive.html

On iOS the status bar is hidden, with a slide effect.