Install setup-envtest utility if not exists

[vaibhavjainwiz]

#424

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[ckadner]

@vaibhavjainwiz -- thanks for your PR. It definitely makes sense to auto-install missing dependencies.

Introducing a local bin directory is a good best practice to avoid system-wide side effects. However, we already have an established precedent for using the GOBIN to install required CLIs. Both for the Makefile as well as in Dockerfile.develop.

When I tested your changes, I ran into an issue when running make test (which creates the local bin/setup-envtest) and then run make run test inside the developer container:

test -s /workspace/bin/setup-envtest || GOBIN=/workspace/bin go install sigs.k8s.io/controller-runtime/tools/setup-envtest@latest
/workspace/bin/setup-envtest: /workspace/bin/setup-envtest: cannot execute binary file

Though the developer container already has a "global" setup-envtest binary in GOBIN.

So, we should either stick with GOBIN instead of a LOCALBIN or do some extra checking for existing CLIs already available in the current environment.

[spolti]

@vaibhavjainwiz is this something that you will continue to work?