core/internal: move containerd and kubernetes to localstorage

This moves the last users of the old 'storage' library onto 'localstorage'. We move a lot of 'runtime' directories to a single `/ephemeral` root. This could be called `/run`, but that might imply FHS compliance - which we don't have, nor want to have.

We also slightly refactor Kubernetes services to be a bit nicer to spawn. But generally, this is a pure refactor, with no functional changes.

Test Plan: this should fail. part of a larger stack. D590 is the first tip of the stack that should work.

X-Origin-Diff: phab/D589
GitOrigin-RevId: d2a7c0bb52c2a7c753199221c609e03474936c22
diff --git a/core/internal/containerd/config.toml b/core/internal/containerd/config.toml
index 415391a..75d0a69 100644
--- a/core/internal/containerd/config.toml
+++ b/core/internal/containerd/config.toml
@@ -1,13 +1,13 @@
 version = 2
 root = "/data/containerd"
-state = "/containerd/run"
+state = "/ephemeral/containerd"
 plugin_dir = ""
 disabled_plugins = []
 required_plugins = []
 oom_score = 0
 
 [grpc]
-  address = "/containerd/run/containerd.sock"
+  address = "/ephemeral/containerd/client.sock"
   tcp_address = ""
   tcp_tls_cert = ""
   tcp_tls_key = ""