Feature request: return parsed params

[paulish]

It would be nice to get parsed parameters after the validation process.

Imagine you have a request:

/**
 * GET /visit/list
 * @summary get list of visits
 * @param {string} some-header-param.header - some header string value
 * @param {boolean} booleanParam.query - some boolean value
 * @param {integer} intParam.query -  some integer value
 */
router.get('/list', validateRequest(), async (req, res) => {
  const someHeaderParam = req.headers[''];
  const {booleanParam, intParam} = req.query;

  // the problem:
  // we need to gather params from header, query, body and path and to convert there values to previously described types
  // here booleanParam and intParam are string and we need to explicitly convert them before use
});

The suggest is to either set some req property to parsed list of params or to introduce another method to simplify request object parsing.