fix: build ooniprobe for linux using debian/amd64 (#552) (#553)

In https://github.com/ooni/probe/issues/1741, we observed that
every attempt to use `docker --platform` along with `debian` for
packaging ooniprobe fails with `SEGFAULT`, except when using
the `debian:oldstable` container.

To fix this issue, in this diff we fix Debian packaging to run on
any debian system (`debian:stable` in our case) provided that we
have `qemu-user-static` installed on the system and the system is
a Debian (or Debian-derived) system.

The trick here is to use `dpkg-buildpackage -a $deb_arch`. We
also need to disable a few `debian/rules` that we don't actually
need anyway.

Closes https://github.com/ooni/probe/issues/1741.

This cherry-picks 36a5bf34f99f382a081efd642dd472888a57602b
from the stable branch into the master branch.

.github/workflows/linux.yml

@@ -4,6 +4,8 @@ on:
   push:
     branches:
       - "release/**"
+      - "stable"
+      - "linux"
 
 jobs:
   build_386: