[clang-refactor] Introduce a new rename rule for qualified symbols

Summary: Prototype of a new rename rule for renaming qualified symbol.

Reviewers: arphaman, ioeric, sammccall

Reviewed By: arphaman, sammccall

Subscribers: jklaehn, cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D39332

llvm-svn: 317672