Helm Charts

[mpstefan]

As a potential user of NKG
I want to use a Helm chart to install the NGINX Kubernetes Gateway
So that I can use one command to install the NGINX Kubernetes Gateway
And so that I can easily update.

Acceptance

• A helm chart to install NKG is accessible to users
• Documentation is added to our installation documentation to show both Helm and YAML methods of installation.
• Users are able to pull from GitHub charts to install.
  • Ingress Controller: https://github.com/nginxinc/kubernetes-ingress/pkgs/container/charts%2Fnginx-ingress
• Users are able to pull both edge and release versions

### Tasks
- [x] Create helm chart files
- [x] Create steps in CI to test and release charts
- [x] Add documentation to show Helm installation
- [x] Add developer docs for local Helm development and testing

[mpstefan]

We want to do a Helm Chart before simplifying our manifests to make maintenance easier.

[mpstefan]

Do we want contain all of our CRDs in a single yaml so they can be replaced by Helm? This should allow an easy upgrade to our CRDs.