Add N and M in the json response
Add N and M in the json response

The label object is added in the response. It contains center index N value
and number of slots M, required by the request according to the computation.

The label object directly follows the hop attribute as detailed in
draft-ietf-teas-yang-path-computation.

If the path is not blocked this changes the index of the last hop information
(-3 instead of -2) and the index of the transponder for the first hop
(2 instead of 1)

Signed-off-by: EstherLerouzic <9136e9bbec0a09a1685b8ebbe677b6c9b26e8f18@orange.com>

Telecominfraproject/gnpy