inversify-express-utils: BaseHttpController's conflict should take an argument

[tgiardina]

This is a feature request for inversify-express-utils. Controllers that extend BaseHttpController have access to a this.conflict method, but this method does not take any arguments. Using this.json is an easy workaround, but I would still like this.conflict to take an optional generic argument.

Expected Behavior

I would expect this.conflict to take a generic argument that allows me to explain why the conflict occurred.

Current Behavior

I cannot provide an argument, so this.conflict just returns a 409 code.

Context

Let's say I get a POST /users request. It may conflict because (1) the provided username already exists or (2) the provided email already exists. The API should return which conflict actually occurred.