Add native-deb* targets to build native Debian packages

In continuation of previous #13451, this commits adds native-deb*
targets for make to build native debian packages. Github workflows
are updated to build and test native Debian packages.

Native packages only build with pre-configured paths (see the
dh_auto_configure section in contrib/debian/rules.in). While
building native packages, paths should not be configured. Initial
config flags e.g. '--enable-debug' are replaced in
contrib/debian/rules.in.

Additional packages on top of existing zfs packages required to
build native packages include debhelper-compat, dh-python, dkms,
po-debconf, python3-all-dev, python3-sphinx.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #14265

scripts/debian-packaging.sh

@@ -1,36 +0,0 @@
-#!/bin/bash
-
-#
-# This script can be used to invoke OpenZFS build from native Debian
-# packaging.
-#
-
-print_help ()
-{
-	echo "Usage: $(basename $0) [OPTIONS]"
-	echo
-	echo "Options:"
-	echo " -b, --build		Build OpenZFS from Debian Packaging"
-	echo " -c, --clean		Clean the workspace"
-}
-
-if [ "$#" -ne 1 ]; then
-	print_help
-	exit 1
-fi
-
-case $1 in
-	-b|--build)
-		cp -r contrib/debian debian
-		debuild -i -us -uc -b && fakeroot debian/rules override_dh_binary-modules
-		;;
-	-c|--clean)
-		fakeroot debian/rules override_dh_auto_clean
-		rm -rf debian
-		;;
-	*)
-		print_help
-		;;
-esac
-
-exit 0