Proposal for a Kubernetes Operator

I created a project where you can deploy and manage (still in a basic form) an Apache Pinot cluster via a Kubernetes Operator. You can find it [here](https://github.com/spaghettifunk/pinot-operator). We could use it as base for an official Apache Pinot Kubernetes Operator ☺️

Start by reviewing the linked pinot-operator project and the Apache Pinot repository to understand the proposed integration. No Pinot files, tests, or entry points are named in the issue, so the scope and acceptance criteria would need to be defined before implementation; done would mean an agreed official Kubernetes Operator direction.

Written by the indexing model from the issue text.