Adding more shell scripts for various tasks

- [ ] For removing all files of particular extension
- [ ] For structuring files into folders based on extensions
- [ ] For finding a particular file

Look at existing scripts in the repository to understand the style and structure. Each task corresponds to a new script: one to remove files by extension, one to organize files into folders by extension, and one to find a file. Start by writing a simple script for one task, test it locally, and ensure it follows the project's conventions. 'Done' means each script works as described and is added to the repo.

由索引模型根據 Issue 內容生成。