Log exception only in with_pool decorator and not for UserError and UserWarning
For now there are logs in with_transaction and user_application decorator. This result in multiple logging of the same exception. Indeed it will be better to only log at the highest level which is with_pool (without it it is only non Tryton code can be used). Also we should not log UserError nor UserWarning but return them as HTTPException as 400 BAD REQUEST.