Added very simple kernel memory allocator

include/allocator.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <stddef.h>
+
+void initialize_allocator(void *bottom, void *top);
+
+void *allocate_from_bottom(size_t size);
+
+void *allocate_from_top(size_t size);