Red code legacy MemoryManager, StreamEngine, ResourceManager, ImageHandler, AsyncPakManager, and more (#758)

Remove from CryCommon and CrySystem:
- MemoryManager and all related classes/files
- StreamEngine, ResourceManager, ImageHandler, and AsyncPakManager
- Various other related interfaces/files/classes etc. that are all now unused

Code/Sandbox/Editor/Util/ImageTIF.cpp

@@ -440,7 +440,6 @@ bool CImageTIF::SaveRAW(const QString& fileName, const void* pData, int width, i
         {
             size_t offset = h * pitch;
             int err = TIFFWriteScanline(tif, raster + offset, h, 0);
-            assert(CryMemory::IsHeapValid());
             if (err < 0)
             {
                 bRet = false;