The /resolve API will take in a template and apply the template extension combination rules to produce the actual template that will be used when creating clusters.
The /resolve API will be useful for debugging purposes, and also the UI.
The /resolve API should give a descriptive error when there's an issue with the template. For example, if the template is trying to override one of the configurations that an immutable partial has set, then the /resolve API should indicate that. If there are multiple errors, the /resolve API should give a list of errors.