Feat/k8s provider (#130)

This PR introduces the Kubernetes Provider for the SDK, with the use of
kube.rs for common operation and a custom file server using axum to
transfer files back and forth the nodes.

https://github.com/paritytech/zombienet-sdk/issues/35



This also includes the refacto of the native provider to reflect changes
to the provider structure with weak references and simplifying the use
of abstractions

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Co-authored-by: Javier Viola <[email protected]>
Co-authored-by: Javier Viola <[email protected]>
Co-authored-by: Javier Viola <[email protected]>