doc: regenerate architecture diagrams
Created by: LawnGnome
As cut, the 3.19
branch appears to fail the dev/check/go-generate.sh
check due to out of date architecture diagrams. These were updated as a whole in #12949, but this missed the 3.19 cut and we might not want to cherry pick the whole thing: this is the minimal PR to get things green again, I believe.
cc: @marekweb @eseliger