Add built-in urlquery.decode_object function

[scevallos]

Expected Behavior

> urlquery.decode_object("?pizza=good&coffee=great&dogs=best")
{
    "pizza": "good",
    "coffee": "great",
    "dogs": "best"
}

Actual Behavior

There is no such function currently. Although, we do have the inverse function available as urlquery.encode_object. This would be helpful for policies that need to make use of URI query parameters.

This is a feature request for such a function to be added.

[tsandall]

The built-in function should deal with cases where the same parameter is specified multiple times. Usually this is handled by returning the values as an array:

urlquery.decode_object("?pizza=good&coffee=great&dogs=best&coffee=mandatory")
{
    "pizza": ["good"],
    "coffee": ["great","mandatory"],
    "dogs": ["best"]
}