tools: bpftool: add support for quotations in batch files

tools: bpftool: add support for quotations in batch files

Improve argument parsing from batch input files in order to support
arguments enclosed between single (') or double quotes ("). For example,
this command can now be parsed in batch mode:

    bpftool prog dump xlated id 1337 file "/tmp/my file with spaces"

The function responsible for parsing command arguments is copied from
its counterpart in lib/utils.c in iproute2 package.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>