tipc: add name table dump to new netlink api

Add TIPC_NL_NAME_TABLE_GET command to the new tipc netlink API.

This command supports dumping the name table of all nodes.

Netlink logical layout of name table response message:
-> name table
    -> publication
        -> type
        -> lower
        -> upper
        -> scope
        -> node
        -> ref
        -> key

Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>