Split the core project into core/kernel/services as it's become a behemoth.

src/kernel/k_interrupt_manager.h

@@ -0,0 +1,18 @@
+// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace Kernel {
+
+class KernelCore;
+
+namespace KInterruptManager {
+void HandleInterrupt(KernelCore& kernel, s32 core_id);
+void SendInterProcessorInterrupt(KernelCore& kernel, u64 core_mask);
+
+} // namespace KInterruptManager
+
+} // namespace Kernel