Add dummy install target for common_documentation, as expected by Buildyard.
Add dummy install target for common_documentation, as expected by Buildyard.

biddisco/CMake,shuaibarshad/KAUST-CMake,shurikasa/CMake,shuaibarshad/KAUST-CMake,ptoharia/CMake,shuaibarshad/KAUST-CMake,shurikasa/CMake,shuaibarshad/KAUST-CMake,ptoharia/CMake,jafyvilla/CMake,ptoharia/CMake,biddisco/CMake,jafyvilla/CMake,shurikasa/CMake,shurikasa/CMake,biddisco/CMake,ptoharia/CMake,jafyvilla/CMake,biddisco/CMake,jafyvilla/CMake