XD-479 Add Inbound and Outbound Conversions

- port David Turanski's JsonRedisSerializer, removing Redis and
    renaming to TypedRedisMapper

- outbound conversion passes byte[] without change and uses the
    TypedJsonMapper for other payloads (except if the transport
    uses MediaType.ALL, no conversion is done - intended for
    local transport(s) only.

- inbound conversion uses the TypedRedisMapper to get back to the
    original object; if the sink doesn't support the type, attempt
    to use the conversion service to convert to a supported type.

- Remove 'from' MediaType - not needed; for outbound if the payload
    is a byte[] send raw - otherwise JSON; for inbound it's self
    describing (but we need a mechanism to short circuit json attempt).

Add tests