As per #4341.
Also reformatted layouts to have a more consistent style.
Also refactored `AppShareRecyclerView` and `AccountDevicesShareRecyclerView` by
defining their LayoutManager in XML to reduce code complexity.
* Closes#2782: Hide send tab when no devices available
* For #2752: Enabled send tab for debug and nightly builds
* For #2753: Add Send Tab functionality to UI