This adds "environments" to the release package that can be used to configure some environment variables. These variables will be loaded either by an `--env` argument or a `env` definition in the test definition and can be used to e.g. run release tests on staging.
OSS release tests currently run with hardcoded Python 3.7 base. In the future we will want to run tests on different python versions.
This PR adds support for a new `python` field in the test configuration. The python field will determine both the base image used in the Buildkite runner docker container (for Ray client compatibility) and the base image for the Anyscale cluster environments.
Note that in Buildkite, we will still only wait for the python 3.7 base image before kicking off tests. That is acceptable, as we can assume that most wheels finish in a similar time, so even if we wait for the 3.7 image and kick off a 3.8 test, that runner will wait maybe for 5-10 more minutes.
Although there's enough quota, it is possible the AWS doesn't have enough capacity to start up new nodes. According to @allenyin55, the current wait for node timeout is too short. This PR increases the timeout to 3000 seconds (50 minutes) from 600 seconds. Let's see if this can resolve the issue. If it makes things worse, I will revert it quickly (I will closely monitor the infra failure rate)
#22749 broke release unit tests by not providing a legacy key - that key should be optional because we will b dealing with non-legacy tests soon.
Additionally, for some reason the unit tests pass on buildkite while they fail locally and in the release test pipeline. I'm investigating this now...
Of all smoke test arguments, frequency is the only required one, so we should check for it. Additionally, not all fields should be able to be overwritten (e.g. legacy or name), so we enforce this as well.
This currently leads to failing builds for schema validation errors after #22901 was merged (the stable column was incorrectly not added to the schema before).
To avoid breakage like in #22905, this PR adds schema validation to the release test package.
In a follow-up PR, we'll likely switch this to use pydantic instead.
