[NETFILTER]: Add CONFIG_NETFILTER_ADVANCED option

The NETFILTER_ADVANCED option hides lots of the rather obscure netfilter
options when disabled and provides defaults (M) that should allow to
run a distribution firewall without further thinking.

Defaults to 'y' to avoid breaking current configurations.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>