ip: add a new parameter -Numeric

ip: add a new parameter -Numeric

Add a new parameter '-Numeric' to show the number of protocol, scope,
dsfield, etc directly instead of converting it to human readable name.
Do the same on tc and ss.

This patch is based on David Ahern's previous patch.

Suggested-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>