m/node/allocs: split new package off m/node

The metropolis/node package contains various unrelated things. One of
these things are node-wide allocations of identifiers.
These are moved here to the new metropolis/node/allocs package.
Additionally, the constants are renamed to move the type of identifier
in front.

Change-Id: Ibc841ca64d4450a7054463e6d2d44753a118e07a
Reviewed-on: https://review.monogon.dev/c/monogon/+/4566
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/kubernetes/pki/BUILD.bazel b/metropolis/node/kubernetes/pki/BUILD.bazel
index 60121c7..85e0d2f 100644
--- a/metropolis/node/kubernetes/pki/BUILD.bazel
+++ b/metropolis/node/kubernetes/pki/BUILD.bazel
@@ -6,7 +6,7 @@
     importpath = "source.monogon.dev/metropolis/node/kubernetes/pki",
     visibility = ["//metropolis/node:__subpackages__"],
     deps = [
-        "//metropolis/node",
+        "//metropolis/node/allocs",
         "//metropolis/node/core/consensus",
         "//osbase/pki",
         "@io_etcd_go_etcd_client_v3//:client",