Remove 'qs' dependency

[clarkf]

'qs' (package, source) appears to be unused since 34c5598 (PR #2719), and can be safely removed.

It's worth noting that 'qs' has the deepest dependency graph of all (non-development) dependencies.

$ npm ls --depth=32 --omit=dev
...
├─┬ [email protected]
│ └─┬ [email protected]
│   ├─┬ [email protected]
│   │ ├── [email protected]
│   │ └── [email protected] deduped
│   ├─┬ [email protected]
│   │ ├── [email protected] deduped
│   │ ├── [email protected]
│   │ └─┬ [email protected]
│   │   └── [email protected] deduped
│   └── [email protected]
...

No other dependencies have more than one level of nesting.

#244 is relevant here (maybe?), though this doesn't go particularly far. A full dev install still weighs 372M on my machine, though this reduces a production install from 9.3M to 8.6M.

Checklist

• Tests written for new code (and old code if feasible)
• Linter and other CI checks pass
• Sign-off given on the changes (see CONTRIBUTING.md)

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This change is marked as an internal change (Task), so will not be included in the changelog.

[turt2live]

Thanks! Looks like we indeed don't use this dependency.

Just one comment about the lockfile before we can merge this.

[turt2live]

thanks :)