Instead of exposing fence value to wait in header, user setter/getter methods. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7057>
Adding d3d12ipcsink and d3d12ipcsrc elements, equivalent to D3D11 ones. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6428>