Ready more build rules for dir move

Tweak some visibilities and set up more filegroups to enable moving
the ApiDocs.bp and StubLibraries.bp files into the api subdir.

Bug: 271563074
Test: m
Change-Id: Ib2776dfc6c67b2042fb2f43a1251cd6f0ba61dc7
diff --git a/StubLibraries.bp b/StubLibraries.bp
index b005591..f08745b 100644
--- a/StubLibraries.bp
+++ b/StubLibraries.bp
@@ -515,6 +515,7 @@
     ],
     api_levels_sdk_type: "public",
     extensions_info_file: ":sdk-extensions-info",
+    visibility: ["//frameworks/base"],
 }
 
 droidstubs {