Indicate which files don't have "sideEffects" in package.json for improved tree shaking

[CraigMacomber]

I think (but have not confirmed) that part of the reason I'm seeing more TypeBox code get included in my bundle than expected is because TypeBox does not specify "sideEffects": false in its package.json file.

Assuming TypeBox does not rely on import side-effects, including that should improve tree shaking in webpack based bundles, see https://webpack.js.org/guides/tree-shaking/