feat: extract preview and fullscreen actions from three-dot-menu

[Macavity]

This PR explodes the preview/edit-toggle and the full-screen button from the three-dots menu as suggested in #366. In the discussion it sounded like it would be an idea to only extract the preview/edit-toggle, but as only the fullscreen was left in the menu, that didn't seem reasonable.

Two screenshots what the result looks like:

Open for any feedback, the discussion in #366 has been stale for while already.