Consider replacing `qs` with `URLSearchParams`

[wojtekmaj]

Is your feature request related to a problem?

qs is pulling in 14 other dependencies with it: https://npmgraph.js.org/?q=qs@6.12.3, making swagger-js installing, evaluating and running slower than it could. On top of that, since qs is being maintained by you-know-who, changes are that even more needless dependencies will pop up in the dependency tree.

Describe the solution you'd like

Consider replacing qs with URLSearchParams.

Describe alternatives you've considered

Custom function like:

function stringify(obj) {
    function stringifyInner(obj, parentKey) {
        return Object.entries(obj).flatMap(([key, value]) => {
            const fullKey = `${parentKey}[${key}]`;
            if (typeof value === 'object') return stringifyInner(value, fullKey)
            return [[fullKey, value]]
        })
    }
    return new URLSearchParams(Object.entries(obj).flatMap(([k, v]) => {
        if (typeof v === 'object') return stringifyInner(v, k)
        return [[k, v]]
    }));
}

if nested value support would be needed.

[char0n]

Started the effort in #3633

[char0n]

@wojtekmaj addressed in #3634. I would appreciated your review.