upgrade to adopt the latest jupyterhub feature about ml-hub

[ClementGautier]

I was going to make some changes in the helm chart but saw that most of what I'm trying to solve is already fixed in https://github.com/jupyterhub/zero-to-jupyterhub-k8s/tree/main/jupyterhub

@raethlein : would you consider removing all jupyterhub related things from this repository and use the helm chart from jupyterhub as dependency?

[raethlein]

Hey @comeUpWithItLater and @ClementGautier, thanks for looking into this!
I think using the official jupyterhub helm chart would be great as this would be one less dependency to care about. Back then I think the decision to copy the helm chart / parts of it to this repo was that we needed to make some slight modifications (e.g. setting some environment variables, opening another port for ssh access etc.) that was not directly configurable in the jupyterhub helm chart. I have to look into the newest helm chart version to see whether it could not be easily configured without the need to copy it here