v5 - Add query() route method for HTTP QUERY (RFC 10008)

[odan]

Add a query() method on App, Router, and RouteGroup for the HTTP QUERY verb (RFC 10008).

QUERY is a safe, idempotent method that may include a request body, so it is a better fit than GET for searches and other parameterized lookups.

Usage

$app->query('/search', function ($request, $response) {
    return $response;
});

[odan]

@akrabat Please check and approve for v5.

[coveralls]

coverage: 96.41% (+0.004%) from 96.406% — odan:v5-query into slimphp:5.x