Figure out + document how to use manual capture profiling with Kubernetes

[skye]

https://jax.readthedocs.io/en/latest/profiling.html#manual-capture-via-tensorboard

This recently came up with a GKE user. We didn't know how to expose the port used by jax.profiler.start_server so it can be accessed from a TensorBoard instance (or maybe the best way is to start a TB instance on the cluster and access that somehow?). Given that it's very common to use JAX with Kubernetes, it would be nice if we could figure this out and provide a working recipe.