Give core registry libraries public visibility

This is so Donuts can create entirely separate Bazel repositories that
link against the Domain Registry codebase.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116182448

java/com/google/domain/registry/security/BUILD

@@ -9,6 +9,7 @@ java_library(
         ["*.java"],
         exclude = glob(["*Servlet.java"]),
     ),
+    visibility = ["//visibility:public"],
     deps = [
         "//java/com/google/common/base",
         "//java/com/google/common/collect",