Explore merging development and CI environments

[kocolosk]

Overview

Just a work in progress right now, but the ideas I'm exploring include:

1. Using the same container image for PRs in Jenkins and as the default container environ in e.g. VS Code
2. Converting over to the official Erlang container images so we can automatically stay up-to-date with patch releases
3. Using a separate FDB container for the FDB server and linking it to the development environment

Testing recommendations

Opening a PR to see how Jenkins handles the linked container approach. I'm intending to follow the pattern from https://www.jenkins.io/doc/book/pipeline/docker/#running-sidecar-containers

Checklist

• [ ] Code is written and works correctly
• [ ] Changes are covered by tests
• [ ] Any new configurable parameters are documented in rel/overlay/etc/default.ini
• [ ] A PR for documentation changes has been made in https://github.com/apache/couchdb-documentation