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>
Hide most of symbols of GstD3D11Memory object.
GstD3D11Memory is one of primary resource for imcoming d3d11 library
and it's expected to be a extensible feature.
Hiding implementation detail would be helpful for later use case.
Summary of this commit:
* Now all native Direct3D11 resources are private of GstD3D11Memory.
To access native resources, getter methods need to be used
or generic map (e.g., gst_memory_map) API should be called
apart from some exceptional case such as d3d11decoder case.
* Various helper methods are added for GstBuffer related operations
and in order to remove duplicated code.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1892>
