treewide: introduce osbase package and move things around

All except localregistry moved from metropolis/pkg to osbase,
localregistry moved to metropolis/test as its only used there anyway.

Change-Id: If1a4bf377364bef0ac23169e1b90379c71b06d72
Reviewed-on: https://review.monogon.dev/c/monogon/+/3079
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/metropolis/test/util/rpc.go b/metropolis/test/util/rpc.go
index e4caece..030d8d0 100644
--- a/metropolis/test/util/rpc.go
+++ b/metropolis/test/util/rpc.go
@@ -9,7 +9,7 @@
 	"testing"
 
 	"source.monogon.dev/metropolis/node/core/identity"
-	"source.monogon.dev/metropolis/pkg/pki"
+	"source.monogon.dev/osbase/pki"
 )
 
 // NewEphemeralClusterCredentials creates a set of TLS certificates for use in a