Parsing Postman collections fail when the Items arrays are nested

[darrelmiller]

Postman collections have a property called item that is an array of objects where each object can either be an item that has a request property, or an item group which is an array of items. This allows the collection to be a tree of folders that contain requests.

Hidi currently fails when it finds an item that doesn't have a request object. It also doesn't navigate into items that are arrays of items.