improvement: add in query param representation to the IR

[armandobelardo]

Updates query parameters to specify the way they should be represented within the resultant HTTP request. Specifically, for parameters that are lists, we allow for two types of representations:

• exploded = a="one"&a="two"&a="three"
• comma-separated = a=one,two,three,four

[dannysheridan]

@armandobelardo can you merge or close this PR?