Add documentation for bpftool.  Separate files for each subcommand.
Use rst format.  Documentation is compiled into man pages using
rst2man.
Signed-off-by: NDavid Beckett <david.beckett@netronome.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>