Adding filterable datagrid

Many open-source JavaScript libraries come with datagrids that have filtering capabilities, but there isn't a large library that does this on the .NET Desktop side; there are small attempts, but they aren't fully functional.

Material Design in XAML is probably the most used UI library in WPF. Therefore, a new control as a filterable datagrid, or an extension to an existing datagrid, would take .NET Desktop a step forward.

Issue 中没有指定文件、测试或入口点。首先检查仓库中现有的 WPF 控件和与 datagrid 相关的支持；要视为完成，需要一个达成共识的设计，以及一个可正常工作的可筛选 datagrid 或集成到 toolkit 中的扩展。