Move RingBuffer to SystemUICommon.

This change adds a new module SystemUICommon and moves RingBuffer to
it. This is to prepare introducing a new logging library which would
depend on it.

Bug: 276475093
Test: RingBuffer does not have existing tests, so just verified
LogBuffer works correctly on device

Change-Id: Ib71fcf8526021be1ac3fe279210c54cb7d4cd0e6
diff --git a/packages/SystemUI/plugin/Android.bp b/packages/SystemUI/plugin/Android.bp
index fb1c454..e306d4a 100644
--- a/packages/SystemUI/plugin/Android.bp
+++ b/packages/SystemUI/plugin/Android.bp
@@ -37,6 +37,7 @@
         "error_prone_annotations",
         "PluginCoreLib",
         "SystemUIAnimationLib",
+        "SystemUICommon",
     ],
 
 }