feat: Add Github workflows to lint and release Helm chart

[0xThresh]

This PR adds Github Actions workflows that can run helm lint on the Helm charts, and release Helm charts to Github using Github Pages as a publishing source.

Action Required - Set Up gh-pages Branch
Before the Helm release workflow will work correctly, there is setup required by a maintainer. The steps can be found in the Helm docs, and should only take about 5 minutes.

A successful test run of this workflow can be seen in my fork here: https://github.com/0xThresh/vllm-production-stack/actions/runs/12979140685/job/36194506180

And you can see the charts that I successfully published on my repo here: https://0xthresh.github.io/vllm-production-stack/index.yaml

While I hope this is a helpful PR, I also understand if there are other plans for chart publishing. If that is the case, I hope the Lint workflow is still helpful, and can update my PR to only include that. Thank you!

[ApostaC]

LGTM! Thanks for the contribution!