Kernel: Move all Graphics-related code into Devices/GPU directory

Like the HID, Audio and Storage subsystem, the Graphics subsystem (which
handles GPUs technically) exposes unix device files (typically in /dev).
To ensure consistency across the repository, move all related files to a
new directory under Kernel/Devices called "GPU".

Also remove the redundant "GPU" word from the VirtIO driver directory,
and the word "Graphics" from GraphicsManagement.{h,cpp} filenames.

Kernel/Devices/GPU/Generic/DisplayConnector.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Try.h>
+#include <Kernel/Devices/GPU/Console/GenericFramebufferConsole.h>
+#include <Kernel/Devices/GPU/DisplayConnector.h>
+#include <Kernel/Library/LockRefPtr.h>
+#include <Kernel/Locking/Spinlock.h>
+#include <Kernel/Memory/TypedMapping.h>
+
+namespace Kernel {
+
+class GenericDisplayConnector
+    : public DisplayConnector {
+    friend class DeviceManagement;
+
+public:
+    static NonnullLockRefPtr<GenericDisplayConnector> must_create_with_preset_resolution(PhysicalAddress framebuffer_address, size_t width, size_t height, size_t pitch);
+
+protected:
+    ErrorOr<void> create_attached_framebuffer_console();
+
+    GenericDisplayConnector(PhysicalAddress framebuffer_address, size_t width, size_t height, size_t pitch);
+
+    virtual bool mutable_mode_setting_capable() const override final { return false; }
+    virtual bool double_framebuffering_capable() const override { return false; }
+    virtual ErrorOr<void> set_mode_setting(ModeSetting const&) override { return Error::from_errno(ENOTSUP); }
+    virtual ErrorOr<void> set_safe_mode_setting() override { return {}; }
+    virtual ErrorOr<void> set_y_offset(size_t) override { return Error::from_errno(ENOTSUP); }
+    virtual ErrorOr<void> unblank() override { return Error::from_errno(ENOTSUP); }
+
+    virtual bool partial_flush_support() const override final { return false; }
+    virtual bool flush_support() const override final { return false; }
+    // Note: This is "possibly" a paravirtualized hardware, but since we don't know, we assume there's no refresh rate...
+    // We rely on the BIOS and/or the bootloader to initialize the hardware for us, so we don't really care about
+    // the specific implementation and settings that were chosen with the given hardware as long as we just
+    // have a dummy framebuffer to work with.
+    virtual bool refresh_rate_support() const override final { return false; }
+
+    virtual ErrorOr<void> flush_first_surface() override final;
+
+    virtual void enable_console() override final;
+    virtual void disable_console() override final;
+
+    LockRefPtr<Graphics::GenericFramebufferConsole> m_framebuffer_console;
+};
+}