Rewrite NamespaceUtils to be non-static and use one instance

On a medium-size item, NamespaceUtils::getEntityNamespace 
was called 935 times, taking noticeable amount of time
in profiling results.

Change-Id: I9de1c739581a4e2fb0aaaef4cb6506a90e29f2b8
Merge "Rewrite NamespaceUtils to be non-static and use one instance"