* shell.nix: Add buildah and kind

* buildah: Allow loading images into kind cluster

* Makefile: Add targets to setup and use kind for tests

* [charts/{c*-migrations,es-index}] Allow setting imagePullPolicy

* buildah: Also build spar-migrate-data

* federation-tests.sh: Run tests with correct pattern

* Set imagePullPolicy to Never only in the kind cluster

* Makefile: use absolute location for kind-kubeconfig

* Makefile/buildah: Default to loading images in the kind cluster

* dev-docs: Document the new kind based flow

Co-authored-by: jschaul <jschaul@users.noreply.github.com>