Return 204 when possible

[GrandChaman]

Some requests return no useful data. Their status code should be HTTP 204

• For create requests where all the provided field are returned as is, the response should also be HTTP 204
• For update requests where no other fields has been updated apart from those specified by the requests, the response should also be HTTP 204 as per the JSON:API specs
• For delete operation, return HTTP 204 when nothing is returned