- Add CMakeLists.txt to build all T tracer user tools
- Previous Makefiles are retained in common/utils/T: you can do
  $ cd common/utils/T/tracer
  $ make # all executables are there
  or also
  $ mkdir build && cd build
  $ cmake .. -GNinja
  $ ninja T_tools # all executables are in build/common/utils/T/tracer