Documentation preview per pull requestion with URL commented

[samiralavi]

The documentation of Aqueduct can not be previewed in a PR that has changed the docs because there is no staging environment or workflow for that. An idea taken from FastAPI repository is to use Cloudflare Pages service which is a free service to host staging static website. Further information about how it works is here:

https://github.com/cloudflare/pages-action https://github.com/tiangolo/fastapi/blob/master/.github/workflows/deploy-docs.yml