Leverage the multicluster-runtime library to enable the operator to manage resources from many control planes.

The Datum multicluster provider library has been copied from the
network-services-operator project. A future iteration will move the
provider into its own library that can be shared across projects. We
decided to copy the code until it's stabalized, which it seems to be
nearing.

Additional changes include:

- Addition of structured configuration provided via a config file, with
  support for default values.
- Support for reading webhook certificates from secrets, simplifying
  development.

Author: joshlreese

Makefile

@@ -48,8 +48,9 @@ manifests: controller-gen ## Generate WebhookConfiguration, ClusterRole and Cust
 	$(CONTROLLER_GEN) rbac:roleName=manager-role crd:generateEmbeddedObjectMeta=true webhook paths="./..." output:crd:artifacts:config=config/crd/bases
 
 .PHONY: generate
-generate: controller-gen ## Generate code containing DeepCopy, DeepCopyInto, and DeepCopyObject method implementations.
+generate: controller-gen defaulter-gen
 	$(CONTROLLER_GEN) object:headerFile="hack/boilerplate.go.txt" paths="./..."
+	$(DEFAULTER_GEN) ./internal/config --output-file=zz_generated.defaults.go
 
 .PHONY: fmt
 fmt: ## Run go fmt against code.
@@ -96,9 +97,7 @@ build: manifests generate fmt vet ## Build manager binary.
 
 .PHONY: run
 run: manifests generate fmt vet ## Run a controller from your host.
-# TODO(jreese) add flags for cert dir, cert name, key name instead of messing
-# with tmpdir
-	TMPDIR=$(LOCALBIN)/tmp go run ./cmd/main.go -health-probe-bind-address 0
+	go run ./cmd/main.go -health-probe-bind-address 0 --server-config ./config/dev/config.yaml
 
 # If you wish to build the manager image targeting other platforms you can use the --platform flag.
 # (i.e. docker build --platform linux/arm64). However, you must enable docker buildKit for it.
@@ -143,12 +142,6 @@ endif
 .PHONY: install
 install: manifests kustomize ## Install CRDs into the K8s cluster specified in ~/.kube/config.
 	$(KUSTOMIZE) build config/dev | $(KUBECTL) apply -f -
-	$(KUBECTL) wait --for=condition=Ready -n kube-system certificate/workload-operator-serving-cert
-	mkdir -p $(LOCALBIN)/tmp/k8s-webhook-server/serving-certs
-	$(KUBECTL) get secret -n kube-system workload-operator-webhook-server-cert -o json \
-		| jq -r '.data["tls.crt"] | @base64d' > $(LOCALBIN)/tmp/k8s-webhook-server/serving-certs/tls.crt
-	$(KUBECTL) get secret -n kube-system workload-operator-webhook-server-cert -o json \
-		| jq -r '.data["tls.key"] | @base64d' > $(LOCALBIN)/tmp/k8s-webhook-server/serving-certs/tls.key
 
 .PHONY: uninstall
 uninstall: manifests kustomize ## Uninstall CRDs from the K8s cluster specified in ~/.kube/config. Call with ignore-not-found=true to ignore resource not found errors during deletion.
@@ -174,12 +167,14 @@ $(LOCALBIN):
 KUBECTL ?= kubectl
 KUSTOMIZE ?= $(LOCALBIN)/kustomize
 CONTROLLER_GEN ?= $(LOCALBIN)/controller-gen
+DEFAULTER_GEN ?= $(LOCALBIN)/defaulter-gen
 ENVTEST ?= $(LOCALBIN)/setup-envtest
 GOLANGCI_LINT = $(LOCALBIN)/golangci-lint
 
 ## Tool Versions
 KUSTOMIZE_VERSION ?= v5.5.0
 CONTROLLER_TOOLS_VERSION ?= v0.16.4
+DEFAULTER_GEN_VERSION ?= v0.32.3
 ENVTEST_VERSION ?= release-0.19
 GOLANGCI_LINT_VERSION ?= v2.1.5
 
@@ -193,6 +188,11 @@ controller-gen: $(CONTROLLER_GEN) ## Download controller-gen locally if necessar
 $(CONTROLLER_GEN): $(LOCALBIN)
 	$(call go-install-tool,$(CONTROLLER_GEN),sigs.k8s.io/controller-tools/cmd/controller-gen,$(CONTROLLER_TOOLS_VERSION))
 
+.PHONY: defaulter-gen
+defaulter-gen: $(DEFAULTER_GEN) ## Download defaulter-gen locally if necessary.
+$(DEFAULTER_GEN): $(LOCALBIN)
+	$(call go-install-tool,$(DEFAULTER_GEN),k8s.io/code-generator/cmd/defaulter-gen,$(DEFAULTER_GEN_VERSION))
+
 .PHONY: envtest
 envtest: $(ENVTEST) ## Download setup-envtest locally if necessary.
 $(ENVTEST): $(LOCALBIN)