Improve CI/CD for Helm charts

[RobertKeyser]

Description of Changes

This PR improves the CI/CD/release process for versions of the Fides Helm chart.

A few things happening here:

• Switching to the pre-made GH Action workflow for chart releaser. This will (in addition to adding to the GH releases) curate the chart repository so it can be easily pulled into other projects. This uses the GitHub Pages (via the gh-pages branch) to serve the index.yaml file.
• Improve usability documentation
• Automatically open a PR when there's a new version of Fides released (will also need a corresponding workflow on the Fides repo's GH Actions). It does this by incrementing the chart's appVersion to the released Fides version and also incrementing the Helm Chart's semver-based version. This might get a bit cumbersome if we're also working on PRs and a new version of Fides is released, but I think it might be a good way of helping the Helm chart stay up-to-date.

Pre-merge Checklist

• All CI Pipelines Succeeded
• Documentation Updated
• Relevant Follow-Up Issues Created

[daveqnet]

Approved!