Also restructure this, explaining the Rust data types, and then
explaining the differences with the proto implementation, which uses
"entry" since cl/30296.
Change-Id: Ie264ab60998f0d891b4a4ea680a2d9dbe1c5929e
Reviewed-on: https://cl.snix.dev/c/snix/+/30314
Autosubmit: Florian Klink <flokli@flokli.de>
Reviewed-by: Domen Kožar <domen@cachix.org>
Tested-by: besadii
