Implement support for multiple Query params with same name

[kovalu]

In REST it's common to have query string params with same name, to get multiple values added to 1 variable, example:
myservice.com?param=value1&param=value2

But with RestAssured.Net the .Query(key, value) method is using Dictionary and adds only 1st query param with that name, others are ignored.

Please implement support for providing multiple values.
Possible syntax:

.Query("param", "value1").Query("param", "value2")

OR

.Query("param", "value1", "value2")

[sferencik]

It seems this behaviour is "in line" with HttpUtility.ParseQueryString, which also discards duplicates. However, https://github.com/dotnet/corefx/issues/32575 suggests they are fixing it as we speak. Multiple query params with identical keys should be supported.