Add hooks for altering form data before upload to Hubspot

Problem/Motivation

It could be useful to alter the form submission data during post, either in the context of the webform or at least in the context of the submission to hubspot. I think both hooks would be beneficial to developers as you may want to have the context and form data when altering the webform mapping but also you may use the upload hook outside of a webform and desire the alter context there as well.