Rearrange memory bootstrapping code.

Move EFI-related code and initial memory manager bootstrap code
to memory_bootstrap.cpp, move memory page structs to their own
memory_page.h/cpp files.

src/kernel/memory_pages.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <stdint.h>
+
+#include "kutil/enum_bitfields.h"
+
+enum class page_block_flags : uint32_t
+{
+	// Not a flag value, but for comparison
+	free         = 0x00000000,
+
+	used         = 0x00000001,
+	mapped       = 0x00000002,
+	pending_free = 0x00000004,
+
+	nonvolatile  = 0x00000010,
+	acpi_wait    = 0x00000020,
+
+	permanent    = 0x80000000,
+
+	max_flags
+};
+IS_BITFIELD(page_block_flags);
+
+struct page_block
+{
+	uint64_t physical_address;
+	uint64_t virtual_address;
+	uint32_t count;
+	page_block_flags flags;
+	page_block *next;
+
+	bool has_flag(page_block_flags f) const { return bitfield_contains(flags, f); }
+	uint64_t end() const { return physical_address + (count * 0x1000); }
+
+	page_block * list_consolidate();
+	void list_dump(const char *name = nullptr);
+};
+
+struct page_table_indices
+{
+	page_table_indices(uint64_t v) :
+		index{
+			(v >> 39) & 0x1ff,
+			(v >> 30) & 0x1ff,
+			(v >> 21) & 0x1ff,
+			(v >> 12) & 0x1ff }
+	{}
+
+	uint64_t & operator[](size_t i) { return index[i]; }
+	uint64_t index[4];
+
+	void dump();
+};