Deployment with backwards compatibility

[Stefterv]

I've added this repo to the Processing foundation Netlify and it publishes here https://contributions-preview.processing.org/contribs.txt

I've also looked into setting up an GitHub Action to deploy the contribs.txt to a release instead so we keep everything within the same repo.

In any case I suggest we add a redirect in Netlify on the processing-website https://docs.netlify.com/routing/redirects/redirect-options/ e.g. https://processing.org/contributions/contribs.txt

[Stefterv]

I've added the https://github.com/processing/processing-contributions/tree/main/netlify/edge-functions folder for further backwards compatibility