Move from continuous helmify to custom chart

[mowies]

Goal

Right now, we run Helmify every time something changes in the manifests so that the helm chart is updated accordingly.
This should be changed in favor of having a fully custom chart which is maintained manually. This will enable us to build in custom features that are not supported by Helmify.

Details

• remove helmify from makefiles
• remove helm kustomize overlay in helm/overlay
• remove the entire helm-build and diff in validate-helm-chart (basically leave there only the check for helm docs)
• remove the verify-helm pipeline file
• remove " make helm-package" from the install action

DoD

• helmify is removed from Makefile(s)
• pipelines are green

[RealAnna]

@mowies should we have an extra ticket for a new step in the helm validation pipeline? Something that fails if there is no change in the templates folder but there is change in one or more file in the operators configs?