ebtables: Use do_parse() from xshared

ebtables: Use do_parse() from xshared

Drop the custom commandline parsers from ebtables and
ebtables-translate, extend and use the shared one instead.

ebtables gains a few new features from doing this:

- Rule counters may be specified in the '-c N,M' syntax
- Support for --replace command
- Support for --list-rules command
- Zero individual rules

There is one known regression in this patch, namely maximum chain name
length shrinks to 28 characters (from 32). Since this limit changed for
iptables in the past as well (e.g. with commit 5429b41c2bb4a), assume
nobody really relies upon it anyway.

Signed-off-by: Phil Sutter <phil@nwl.cc>