Investigate increasing developer productivity with pull requests environments

I would like to make life easier for existing and new Hasura contributors including maintainers by implementing [Uffizzi](https://uffizzi.com/) previews.
Disclaimer: I work on Uffizzi
Uffizzi is a Open Source full stack previews engine and is free for Hasura. This will provide newcomers with previews of their PRs in the cloud, allowing them iterate faster, without having to first set up a complete development environment themselves.

TODO:

- [ ] Intial POC

Start by reviewing the proposed Uffizzi pull request preview service and the repository's existing contribution and deployment setup. Define the scope of the initial POC, including how previews would be created for pull requests. Done means a documented, working POC that provides a preview for a Hasura pull request.

Written by the indexing model from the issue text.