adding device selection, buffer creation and pipeline creation to Metal backend

Sources/Backends/Metal/MetalDevice.h

@@ -0,0 +1,26 @@
+// Copyright (C) 2025 kanel
+// This file is part of "Pulse"
+// For conditions of distribution and use, see copyright notice in LICENSE
+
+#include <Pulse.h>
+
+#ifdef PULSE_ENABLE_METAL_BACKEND
+
+#ifndef PULSE_METAL_DEVICE_H_
+#define PULSE_METAL_DEVICE_H_
+
+#include <Metal/Metal.h>
+#include "Metal.h"
+
+typedef struct MetalDevice
+{
+	id<MTLDevice> device;
+	id<MTLCommandQueue> queue;
+} MetalDevice;
+
+PulseDevice MetalCreateDevice(PulseBackend backend, PulseDevice* forbiden_devices, uint32_t forbiden_devices_count);
+void MetalDestroyDevice(PulseDevice device);
+
+#endif // PULSE_METAL_DEVICE_H_
+
+#endif // PULSE_ENABLE_METAL_BACKEND