fix(utils): Support arrays & nested objects in query params

[offirgolan]

Resolves #147.

Adds support for parsing arrays and nested objects in querystrings. To preserve the original querystring structure, I've added logic to determine the original array format used (if any).

The used qs library provides an option to specify the arrayFormat when stringifying:

qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'indices' })
// 'a[0]=b&a[1]=c'
qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'brackets' })
// 'a[]=b&a[]=c'
qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' })
// 'a=b&a=c'

[offirgolan]

Tests are failing in Node 10 in CI that are unrelated to this change since it fails on master as well. Im gonna go ahead and merge.