Missing footer navigation / map on intro page

[Hans Fredrik Nordhaug <hansfn@gmail.com>]

Hi!

I notice that https://www.debian.org/intro/ seems to be the only page
without footermap (except the frontpage). I assume this is because of
MAINPAGE="true" in the template invocation - ref

#use wml::debian::template title="[...]" MAINPAGE="true"

I would like to change this. Any objections?

Hans