Advanced Paste Additional Actions - Paste as file

1. Implemented Paste as file - .txt, .png, .html.
2. Improvements to Image to text - action now enabled only if clipboard contains an image or a single image file.
3. Paste menu - consistent error messages and loading animation for all actions (lots of refactoring involved that should hopefully make it easier to add new actions in the future).
4. Paste menu - both action menus have vertical scroll-bars now and show up to 5 items without manual resizing.
5. Settings screen - moved additional actions into their own section.
6. A few other minor improvements.

Advanced Paste Additional Actions - Image to text

Test release of Advanced Paste Additional Actions with Image to text as the only fully implemented additional action.