[NETFILTER]: Kconfig: improve dependency handling

Instead of depending on internally needed options and letting users
figure out what is needed, select them when needed:

- IP_NF_IPTABLES, IP_NF_ARPTABLES and IP6_NF_IPTABLES select
  NETFILTER_XTABLES

- NETFILTER_XT_TARGET_CONNMARK, NETFILTER_XT_MATCH_CONNMARK and
  IP_NF_TARGET_CLUSTERIP select NF_CONNTRACK_MARK

- NETFILTER_XT_MATCH_CONNBYTES selects NF_CT_ACCT

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