Improve interface to CMake

[marcodelapierre]

Hi @dipietrantonio ,

following feedback from a PaCER project, I think the module that loads the path for ROCm should also update the following variable, for use by CMake, with two new paths:

export CMAKE_PREFIX_PATH="$CMAKE_PREFIX_PATH:<ROCM-HOME>:<ROCM-HOME>/hip"

where is the base installation directory of the ROCm software.