[Feat/Theme]: Liquid Glass Theme

### Is there an existing issue that is already proposing this?

- [x] I have searched the existing issues

### 🪄 describe your feature or idea

Liquid Glass Theme

Document: [HOW_TO_ADD_THEME.md](https://github.com/widgetify-app/widgetify-extension/blob/main/src/styles/theme/HOW_TO_ADD_THEME.md)