Add basic paging support via PagedCollectionView

I propose that that the [PagedCollectionView](https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd538382(v=vs.95)) and the corresponding [IPagedCollectionView](https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd491235(v=vs.95)) from Silverlight are added to WPF.

While it might be possible to get a better implementation it seems just taking the existing code from the Silverlight codebase and adopting the existing API as is seems to be the most straightforward and easiest way to get basic support for paging without having to put a lot of making a new API.

Having a standardized interface such as IPagedCollectionView for paging would allow standard controls for paging and make it a lot easier to show a portion of data for example in LOB applications.

- [ ] Add [IPagedCollectionView](https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd491235(v=vs.95))
- [ ] Add [PagedCollectionView](https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd538382(v=vs.95))
- [ ] Add [DataPager](https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd538632(v=vs.95)) control or similar