[idd] transport: abstract LGMP implementation

Introduce transport, frame, and control interfaces with an LGMP factory
backend.

Move LGMP and IVSHMEM implementation details under transport/lgmp and
expose direct frame-buffer memory through a neutral capability.

idd/LGIdd/capture/CSoftwareFrameProcessor.h

@@ -31,9 +31,9 @@ private:
     CD3D12CommandSlot * slot, bool result, void * param1, void * param2);
 
 public:
-  CSoftwareFrameProcessor(CFrameTransport * transport,
+  CSoftwareFrameProcessor(IFrameTransport * transport,
     std::shared_ptr<CD3D12Device> dx12,
-    CPostProcessor postProcessors[LGMP_Q_FRAME_LEN],
+    CPostProcessor postProcessors[TRANSPORT_FRAME_QUEUE_LENGTH],
     SRWLOCK * pipelineLock, HANDLE terminateEvent);
 
   bool Submit(const FrameSubmission& submission) override;