Standardize HTTP update request methods and return codes

[cmagnobarbosa]

Today, this NApp lacks a standard for the HTTP update request methods and successful response code.

Possible Solution:

Use PATCH to modify an existing resource [1, 2] and return the code 204 in success response.
Example:

• Method: enable_interface:
  Description: Enable interfaces in the topology.
  • Today:
    • POST v3/interfaces/switch/<dpid>/enable success response: 200
  • Propose change:
    • PATCH v3/interfaces/switch/<dpid>/enablesuccess response: 204

References:
[1] - https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PATCH
[2] - https://tools.ietf.org/html/rfc5789#section-2