Kernel: Implement new abstract MemoryRegion

MemoryBackedRegion now inherits from this and is used for private
anonymous mappigs. This will make shared mappings and file backed
mappings much easier to implement.

kernel/CMakeLists.txt

@@ -35,6 +35,8 @@ set(KERNEL_SOURCES
 	kernel/Memory/GeneralAllocator.cpp
 	kernel/Memory/Heap.cpp
 	kernel/Memory/kmalloc.cpp
+	kernel/Memory/MemoryBackedRegion.cpp
+	kernel/Memory/MemoryRegion.cpp
 	kernel/Memory/PhysicalRange.cpp
 	kernel/Memory/VirtualRange.cpp
 	kernel/Networking/E1000.cpp