Navigation: Move the renderer class to the main navigation file (#57979)

* Navigation: Move the renderer class to the main navigation file to take advantage of the automatic backporting

* Update the build script to also copy over class files

* prefix with gutenberg

* Add a Gutenberg suffix to class files when they are built

* add gutenberg prefix to functions

* move the built block files to their own dir

* Putting back the render class into the same file as the navigation block

* Update the rendered post rebase

* Fix php unit tests

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Co-authored-by: Riad Benguella <benguella@gmail.com>