Issue 613 - implemented convop POST /v1/contextEntities

### Description
Implemented yet another convop:
POST /v1/contextEntities

Good point.
Right now it is ignored, however as it shares the request::parse routine and response::render, the 'entity' will be accepted and render but other than that completely ignored.
Will FORBID it for the case of /v1/contextEntities/type/{entityId::type}/id/{entityId::id}.