Navigation block - include Categories in allowed blocks

[Sandstromer]

What problem does this address?

In the Navigation block we can already add the Page List block. This is great for theme authors to create a default menu, but it may make more sense in some designs to use post Categories as the default menu instead.

What is your proposed solution?

Including the Categories list as a navigation option would further enhance the Navigation block.

[getdave]

As I see it this is an important piece of missing functionality. Let's make sure it's on the Tracking Issue.

[getdave]

Closing in favour of Automattic/wp-calypso#65012 where there is more discussion