UBUNTU: [Debian] package bpftool in linux-tools-common

UBUNTU: [Debian] package bpftool in linux-tools-common

BugLink: https://bugs.launchpad.net/bugs/1774815
bpftool is a debugging and introspection tool for BPF elements,
developed by the BPF kernel community. Its source code is located in the
kernel repository, at tools/bpf/bpftool. Package it in linux-tools and
linux-tools-common.

Along the binary, package manual pages and bash completion file. Note
that the generated manual page bpf-helpers.7 is NOT packaged, as this
one is now included in the man-pages repository.

bpftool itself is installed under /usr/sbin/, to be consistent with its
Makefile.

Dependency python-docutils is added to Build-Depends-Indep, in order to
provide rst2man which is necessary to build bpftool's manual pages.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>