Kernel: Rewrite whole AML parser

Now AML parsing is actually done while respecting namespaces and
scopes. I implemented the minimal functionality to parse qemu's AML.

Next step is to implement AML interpreting and then we can drop lai
as a dependency.

kernel/include/kernel/ACPI/AML/Node.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <BAN/ByteSpan.h>
+#include <BAN/Optional.h>
+#include <BAN/RefPtr.h>
+#include <BAN/Vector.h>
+
+namespace Kernel::ACPI::AML
+{
+
+	struct Node : public BAN::RefCounted<Node>
+	{
+		enum class Type
+		{
+			Buffer,
+			Device,
+			FieldElement,
+			IndexFieldElement,
+			Integer,
+			Method,
+			Mutex,
+			Name,
+			OpRegion,
+			Package,
+			Processor,
+			Scope,
+			String,
+		};
+		const Type type;
+
+		Node(Type type) : type(type) {}
+		virtual ~Node() = default;
+
+		virtual bool is_scope() const { return false; }
+		virtual BAN::Optional<uint64_t> as_integer() const { return {}; }
+
+		virtual void debug_print(int indent) const = 0;
+	};
+
+	struct ParseContext;
+	struct ParseResult
+	{
+		static ParseResult Failure;
+		static ParseResult Success;
+
+		enum class Result
+		{
+			Success,
+			Failure,
+		};
+
+		ParseResult(Result success) : m_result(success) {}
+		ParseResult(BAN::RefPtr<Node> node) : m_result(Result::Success), m_node(BAN::move(node)) { ASSERT(m_node); }
+
+		bool success() const { return m_result == Result::Success; }
+
+		BAN::RefPtr<Node> node()
+		{
+			ASSERT(m_node);
+			return m_node;
+		}
+
+	private:
+		Result m_result = Result::Failure;
+		BAN::RefPtr<Node> m_node;
+	};
+	ParseResult parse_object(ParseContext& context);
+
+}