Add native Debian Packaging for Linux

Currently, the Debian packages are generated from ALIEN that converts
RPMs to Debian packages. This commit adds native Debian packaging for
Debian based systems.

This packaging is a fork of Debian zfs-linux 2.1.6-2 release.
(source: https://salsa.debian.org/zfsonlinux-team/zfs)

Some updates have been made to keep the footprint minimal that
include removing the tests, translation files, patches directory etc.
All credits go to Debian ZFS on Linux Packaging Team.

For copyright information, please refer to contrib/debian/copyright.

scripts/debian-packaging.sh can be used to invoke the build.

Reviewed-by: Mo Zhou <cdluminate@gmail.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #13451

scripts/debian-packaging.sh

@@ -0,0 +1,36 @@
+#!/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