Ensure helm chart can run on Kubernetes >= v1.25 and improve installation steps

[JoeyC-Dev]

Proposed changes:

1. Replace helm install with helm upgrade --install, which can be used on both initial installation and upgradation scenarios.
2. Migrate old API to the latest API and add compatibility with old API: autoscaling/v2beta1

Supporting point:

• It is easier to use if using helm upgrade --install
• "The autoscaling/v2beta1 API version of HorizontalPodAutoscaler is no longer served as of v1.25." (src: Deprecated API Migration Guide - v1.25 - HorizontalPodAutoscaler) Meantime, v1.24 is EOL 16 months ago. (src: Non-Active Branch history)
  Today if we are using current version of helm chart, it will fail to run if HPA is enabled as the old API is being deleted since v1.25.

  joey [ ~/whoogle-search ]$ helm upgrade --install whoogle ./charts/whoogle
  Error: UPGRADE FAILED: resource mapping not found for name: "whoogle" namespace: "" from "": no matches for kind "HorizontalPodAutoscaler" in version "autoscaling/v2beta1"
  ensure CRDs are installed first

• Make autoscaling/v2 targeting v1.23 as autoscaling/v2 is available since v1.23.

[benbusby]

Sorry for taking so long with this. Thank you for contributing!