Tag editor icon

Currently the icon for the tag editor in the View menu is the `window-new.png`: <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/6d4b45ac-5dbf-4e9a-a6c0-ab927ab9c62f" /> I was surprised to find `tag-selector.png` in the images folder (which is even included in the mapper build through `resources.qrc`), but it's unused: <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/2a5d08fa-62a2-453b-beb4-a081836f9bd5" /> I see three options: 1. Keep <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/6d4b45ac-5dbf-4e9a-a6c0-ab927ab9c62f" /> and remove the superfluous <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/2a5d08fa-62a2-453b-beb4-a081836f9bd5" /> 2. Replace <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/6d4b45ac-5dbf-4e9a-a6c0-ab927ab9c62f" /> by <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/2a5d08fa-62a2-453b-beb4-a081836f9bd5" /> (and change its name to `tag-editor.png`). 3. Use a new icon which better emphasizes the table layout being used by the tag editor: <img width="32" height="32" alt="Image" src="https://github.com/user-attachments/assets/707baff3-d715-488a-8e29-d2ae82207244" /> I personally favor option 3. In case of options 2 and 3 I would update the mapper manual as well.