Kernel: Implement very simple kernel module loading

It's now possible to load a .o file into the kernel via a syscall.
The kernel will perform all the necessary ELF relocations, and then
call the "module_init" symbol in the loaded module.

Kernel/Module.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <AK/String.h>
+#include <AK/Vector.h>
+#include <Kernel/KBuffer.h>
+
+struct Module {
+    String name;
+    Vector<KBuffer> sections;
+};
+
+typedef void* (*ModuleInitPtr)();
+typedef void* (*ModuleFiniPtr)();