Navigation Items: Add transform items in the inspector, a la Group/Row/Stack

[jasmussen]

When you insert a menu item, it can be either a Page Link, a Custom Link, or a variety of other link types. This makes for a lot of very similar items to choose from in the inserter menu. It would be nice if there was just a single block to insert, of which all of these were variations, as ultimately they are all just links, and the variation mainly affects which items to show in the "Recent" menu.

It could then be possible to switch between these items types in the inspector, just like it is for a Group that can transform into a Row or a Stack. Here's a mockup showing those transforms:

• It remains to be decided which items become variations. It can become quite a lot of transforms otherwise, so it would be good to curate a little. Page Link, Custom Link and Home all feel important to include, though.
• It would be a bonus to revisit the descriptions of each varation, so they all span the same number of lines of text, and don't cause a jump when clicking between the transforms.
• Note for the "Page Link" that the link becomes a page selector dropdown. I imagine this page selector would show the same recent pages, with a search box, as the new menu item dialog does.