Support `limits.totalSize` for multipart forms

[TryingToImprove]

This is attempt on trying to add a configuration for limitting the total size of the multipart form instead of the fieldSize and fileSize.

The reason for this is that Next uses this package, however they work with bodySizeLimit and are there ignored causing causing form fields to be truncated (https://github.com/vercel/next.js/issues/59277) since they do not allow configuring the limits which busboy supports

I am sure this is not the correct way, however any guidance will help