Major changes:
* GstD3D11Allocator: This allocator is now device-independent object
which can allocate GstD3D11Memory object for any GstD3D11Device.
User can get this object via gst_allocator_find(GST_D3D11_MEMORY_NAME)
* GstD3D11PoolAllocator: A new allocator implementation for texture pool.
From now on GstD3D11BufferPool will make use of this memory pool allocator
to avoid frequent texture reallocation. That usually happens because
of buffer copy (gst_buffer_make_writable for example)
In addition to that, GstD3D11BufferPool will provide GstBuffer with
GstVideoMeta, because CPU access to a GstD3D11Memory without GstVideoMeta
is almost impossible since GPU drivers needs padding for stride alignment.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2097>
Move d3d11 device, memory, buffer pool and minimal method
to gst-libs so that other plugins can access d3d11 resource.
Since Direct3D is primary graphics API on Windows, we need
this infrastructure for various plugins can share GPU resource
without downloading GPU memory.
Note that this implementation is public only for -bad scope
for now.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/464>
