Use Symfony HttpException to have a proper status code and generalize error message

Problem/Motivation

AuthenticationException returns a 500 error

Steps to reproduce

Generate a token using an invalid credential and the response will be HTTP/1.1 500 500 Service unavailable (with message)

Proposed resolution

Use Symfony HttpException to have a proper HTTP status response and message

Obscure "Invalid X-AUTH-TOKEN" to "Invalid token"