Document the wp JavaScript object

[justintadlock]

Currently the global wp JavaScript object documentation is very outdated and located in the old Codex: https://codex.wordpress.org/Javascript_Reference/wp I was unable to find anything else on this.

We could use a good handbook page that fully documents this object.

I'm not entirely sure whether this should be a ticket for the Block Editor Handbook or the Common APIs Handbook. But I can move this to the Documentation Issue Tracker if that would be a better place.

[justintadlock]

There is some reference to this object in the handbook (hat tip to @juanmaguitar): https://developer.wordpress.org/block-editor/reference-guides/packages/#using-the-packages-via-wordpress-global

[juanmaguitar]

The recently created PR #56294 covers how to work with the wp object