Add Wireguard-based K8s pod networking

This adds a pod networking runnable based on Wireguard which watches all nodes
and adds their K8s IPAM allocations as routes into the kernel & WireGuard. It only depends
on K8s and only performs direct routing.

Test Plan: Manually tested by spinning up a two-node cluster and running two Alpine pods pinging eachother. Can be covered by E2E tests once we can do image preseeding for the test infra (T793).

Bug: T487

X-Origin-Diff: phab/D573
GitOrigin-RevId: ba3fc36f421fd75002f6cf8bea25ed6f1eb457b0
diff --git a/core/internal/kubernetes/apiserver.go b/core/internal/kubernetes/apiserver.go
index 0a740dd..26c258a 100644
--- a/core/internal/kubernetes/apiserver.go
+++ b/core/internal/kubernetes/apiserver.go
@@ -103,7 +103,7 @@
 				pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: config.kubeletClientCert})),
 			args.FileOpt("--kubelet-client-key", "kubelet-client-key.pem",
 				pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: config.kubeletClientKey})),
-			"--kubelet-preferred-address-types=Hostname",
+			"--kubelet-preferred-address-types=InternalIP",
 			args.FileOpt("--proxy-client-cert-file", "aggregation-client-cert.pem",
 				pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: config.aggregationClientCert})),
 			args.FileOpt("--proxy-client-key-file", "aggregation-client-key.pem",