Provide a base ULS RL module and seperate UI language selection

ULS is disabled for anonymous users on WMF projects. But to provide
rest of the features - apis, language database, language selection for
many use cases, we need to provide a minimal ULS. RL module
ext.uls.init does that job now.

For using ULS as interface language selection tool, new RL module
ext.uls.interface is introduced. That will add UI language selection,
webfonts, ime features, if enabled.

Change-Id: I796a7c9cce0de42bf8aa06b26e383e0075dbe1dd