[NUI] Add a new Tizen.NUI.ICustomAwareDeviceFocusAlgorithm.

[NUI] Add a new Tizen.NUI.ICustomAwareDeviceFocusAlgorithm.

This interface takes an additional deviceName argument to GetNextFocusableView().
The deviceName is the name of the device where the key event occurred.

A new deviceName added to GetNextFocusableView() should not affect the current app.

Current apps are using the FocusManager.ICustomFocusAlgorithm interface.
So I created a new Tizen.NUI.ICustomAwareDeviceFocusAlgorithm interface.

for example)
Currently

``` c#
class CustomInterface : FocusManager.ICustomFocusAlgorithm
{
 public View GetNextFocusableView(View current, View proposed, View.FocusDirection direction)
 {
   return proposed;
 }
}
```

If you wnat to do GetNextFocusableView() with deviceName, you can inherit ICustomAwareDeviceFocusAlgorithm.

``` c#
class CustomInterface : Tizen.NUI.ICustomAwareDeviceFocusAlgorithm
{
 // This method is called when a direction key is pressed.
 public View GetNextFocusableView(View current, View proposed, View.FocusDirection direction, string deviceName)
 {
  return proposed;
 }

 // This method is never called.
 public View GetNextFocusableView(View current, View proposed, View.FocusDirection direction)
 {
  return proposed;
 }
}
```

dependency
https://review.tizen.org/gerrit/#/c/platform/core/uifw/dali-toolkit/+/271983/
https://review.tizen.org/gerrit/#/c/platform/core/uifw/dali-csharp-binder/+/271984/