Remove the dependency on g/g hack/scripts

[unmarshall]

Describe the bug: gardener core currently has a LOT of scripts under /hack which brings in a lot of dependencies into the vendor directory. Most of these dependencies are not used by etcd-druid. Via this issue we wish to remove the dependency on g/g /hack/scripts so that we can have leaner vendor directly which should only contain what druid uses.

Expected behavior: Vendor what is used and nothing more than that.

How To Reproduce (as minimally and precisely as possible): NA

Linked issue: #447 Once we remove the dependency then we will also upgrade the go.mod to move to the latest released version of g/g

[unmarshall]

The vendor directly has been removed from g/g but it still makes sense to not have dependency on scripts from g/g as many of the scripts are created for their purpose. We can simplify many scripts.