synopsis: use queryString to parse QueryParam, QueryParams and QueryFlag
packages: servant-server
prs: #1249
description: {

Some APIs need query parameters rewriting, e.g. in order to support
 for multiple casing (camel, snake, etc) or something to that effect.

This could be easily achieved by using WAI Middleware and modyfing
request's `Query`. But QueryParam, QueryParams and QueryFlag use
`rawQueryString`. By using `queryString` rather then `rawQueryString`
we can enable such rewritings.

}