Feature description

Right now, we're not validating whether instance types passed in the configuration are valid when initializing the infrastructure. However, we're doing it for AWS and DigitalOcean. See:

• nebari/src/_nebari/stages/infrastructure/__init__.py

  Line 517 in aed2b92

  available_instances = amazon_web_services.instances(data["region"])

• nebari/src/_nebari/stages/infrastructure/__init__.py

  Line 282 in aed2b92

  available_instances = {_["slug"] for _ in digital_ocean.instances()}

Value and/or benefit

Besides being consistent with what we have with other providers, it would enhance the user's experience when specifying unavailable/non-existing instance types before running into an error halfway through the deployment.

Anything else?

No response