datax 包结构优化

现有包结构将每一个数据同步组件的读取、写入放在的根目录下，不利于职责划分，能否将每一个组件的读取、写入分类放置？

Start by inspecting the repository's current package layout and locating the reader and writer code for each data synchronization component. The issue does not name specific files, tests, or a target structure, so clarify the intended grouping and migration scope before making changes; done means the components are organized by responsibility without breaking existing synchronization behavior.

Written by the indexing model from the issue text.