fix(heap, readme): MemoryAllocator => Heap, update readme

kernel/src/Memory/Heap.hpp

@@ -0,0 +1,29 @@
+#pragma once
+#include "Memmap.hpp"
+
+namespace Memory {
+    class Allocator {
+        LargestSection g_section;
+
+        struct Block {
+            size_t size;
+            Block* next;
+        };
+
+        struct BlockDescriptor {
+            size_t block_size;
+        };
+
+        Block head;
+    public:
+        Allocator(LargestSection section);
+        void* Request(size_t size, bool phys = false);
+        void* Realloc(void* ptr, size_t size);
+        void Free(void *pagePtr);
+
+        void Stress();
+        void Walk();
+    };
+
+    extern Allocator* g_allocator;
+};