add support for kind clusters

What

Sets KUBECONFIG to a direnv-managed file.
Adds a couple of scripts to make developement with kind easier:
- scripts/kind-up.sh Start a kind cluster with a local registry
- scripts/kind-down.sh Delete the kind cluster and its registry
Exposes the REGISTRY as an option to the Makefile and defaults it to localhost:5001, which is the one used by the kind cluster.
The make deploy job now has a dependency on docker-push to get the image into the kind registry.
Sets the image pull policy to "Always" when deploying to ensure that kind pulls the latest image.

Might break some non-kind workflows with the "push" requirement and defaulting to localhost:5001 for the registry.