[Feature][APIServer v2] Support Compute Template in APIServer v2

[machichima]

Why are these changes needed?

APIServer v1 introduced a unique and mandatory feature, Compute Template, which requires users to predefine the amount of CPU and memory resources they need in templates.

APIServer v2 doesn’t require users to predefine templates anymore, but we still want to continue supporting the feature to help v1 users migrate to v2 more easily.

Implementation

1. Unmarshal the incoming request body in a new apiserversdk proxy handler.
2. Extract computeTemplate from the headGroupSpec and workerGroupSpec.
3. Mutate the request body according to the template before marshaling back.

We need 3 new proxy handlers for RayCluster, RayJob, and RayService, respectively. They may be able to share some parts of the implementation.

Related issue number

Checks

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  • This PR is not tested :(