Refactored pkg/netmap package provides JSON converters for
NodeInfo and PlacementPolicy structures, that has been used
by client applications.
It also updates Node structure itself so it is a part of
grpc <-> v2 <-> pkg conversion chain.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
JSON format is rather verbose an inconvenient to be
edited by hand. This commit implements SQL-like
language for representing placement policy.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
