configure.ac, utility.cpp, utility.h: Add 128-bit unsigned integer to string

conversion.  Provides full integer precision if compiler supports '__int128'
(e.g. x86_64 GCC and CLang).
json.cpp, nvmeprint.cpp: Use these new functions.
Makefile.am: Adjust config-vc14 target.

git-svn-id: https://svn.code.sf.net/p/smartmontools/code/trunk@4745 4ea69e1a-61f1-4043-bf83-b5c94c648137