Integration test suite before release

We currently run a test suite on every commit. These tests are designed to be focused and fast.

However, when we release we may want to consider running some larger workflows that test holistic behavior. This might include, for example, reading a 10,000 partition dataset of parquet data from S3, something that is important, but not something that we want to put into our test suite. This might also be a good place to include workflows from downstream projects like RAPIDS and Xarray.

This would be something that the release manager would be in charge of kicking off.

Some things that we would need to do

- Figure out if we want to add this process
- Build a CI system
- Add tests

cc @jacobtomlinson @quasiben @jrbourbeau