Change default platform to gcc9 and update contrib
- Change default platform to gcc9 and LCG96b
- Update to CMake 3.16.2 (taking it from
/cvmfs/lhcb.cern.ch
) - Update to ccache 3.7.7
- Update to ninja 1.10 (release binary)
Supersedes !9 (merged)
Edited by Rosen Matev