hack/kind-setup.sh is too specific about where to find kind

[MikeSpreitzer]

That script insists on what directory to find the kind command in, but kind has multiple ways to install and they do not all put the executable where the script insists on finding it.

[xrstf]

Since #57 we just use command kind to find kind whereever: https://github.com/kcp-dev/helm-charts/blob/main/hack/kind-setup.sh#L8