[kernel] Change heap alloc for better alignment

Created a new util/node_map.h that implements a map that grows in-place.
Now this is used for tracking blocks' size orders, instead of a header
at the start of the memory block. This allows the whole buddy block to
be allocated, allowing for page-aligned (or greater) blocks to be
requested from the heap.

src/libraries/util/util.module

@@ -20,6 +20,7 @@ module("util",
         "util/map.h",
         "util/misc.h",
         "util/no_construct.h",
+        "util/node_map.h",
         "util/pointers.h",
         "util/spinlock.h",
         "util/util.h",