Add more items to the view mode dropdown

This MR adds a new "View Settings" button to replace the "View Mode" button in the default toolbar. The new button adds more frequently-used items to the dropdown menu: zoom, sort by, show additional columns show preview, show in groups, show hidden files, and the view properties dialog. So most view-related actions are now available in the dropdown menu (instead of in the hamburger menu, some hidden deep in its "More" section).

Before: After:

Hamburger before: After:

The original "view_mode" action is kept because it's also used in the main menu (and hamburger when this new button is not visible).