[Feature] Remove the use of Render method of the chartrenderer.Interface

[AleksandarSavchev]

Feature (What you would like to be added):
I would like the use of Render method of the chartrenderer.Interface to be removed from this project (currently used in ./controllers/etcd_controller.go and ./controllers/etcdcopybackupstack_controller.go)

Motivation (Why is this needed?):
The Render method is deprecated in favour of RenderEmbeddedFS and will be removed in the future. For more info check this PR.

Approach/Hint to the implement solution (optional):
The current Render method can be replaced by RenderEmbeddedFS with some changes to file structure or the code can be refactored without the use of these methods.

[shreyas-s-rao]

We have refactored most of etcd-druid codebase now, and the controllers no longer render helm charts. Instead, we use the ResourceOperator model (similar to the g/g component model) to reconcile k8s resources, so we have gotten rid of usage of chartrenderer package. This issue can now be closed.

/close