Deploy dask-gateway using Helm chart

[marcelovilla]

Context

Currently, we're writing our own k8s manifests to deploy dask-gateway. However, there's a Helm chart available: https://github.com/dask/dask-gateway/tree/main/resources/helm/dask-gateway

Value and/or benefit

This would simplify the management of dask-gateway, reduce maintenance on our side, and be more consistent with how we're deploying other services withing Nebari

Anything else?

No response

[marcelovilla]

#2609 was recently merged and it includes the logic to deploy k8s manifests and Helm charts directly instead of doing it via Terraform. I think we should build on top of that approach to deploy the dask-gateway Helm chart.