Add access to DOMParser or some other XPath utility to Insomnia Designer

[cperedo]

When running an XML request API call thru Insomnia Collections, the response body can be parsed thru using XPath variable. That being said, a similar method to parse XML response body is not available in Designer side of Insomnia. The ask is to add JS DOMParser or some other utility to easily unmarshall the XML response on the Designer side of Insomnia.