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/curator.go b/metropolis/test/util/curator.go
index 39b2610..28fa7b1 100644
--- a/metropolis/test/util/curator.go
+++ b/metropolis/test/util/curator.go
@@ -13,7 +13,7 @@
 	apb "source.monogon.dev/metropolis/node/core/curator/proto/api"
 	cpb "source.monogon.dev/metropolis/proto/common"
 
-	"source.monogon.dev/metropolis/pkg/event/memory"
+	"source.monogon.dev/osbase/event/memory"
 )
 
 // TestCurator is a shim Curator implementation that serves pending Watch